Calibrating ranging constellations in wireless networks

Abstract

The present invention relates to a wireless system and method for managing and / or configuring ranging enabled devices to form a ranging constellation that supports ranging based positioning services, and addresses several challenges in determining the need for calibration of ranging services for improved accuracy and / or reduced power consumption.

Description

[Technical field]

[0001] The present invention relates to ranging and positioning services in wireless networks, such as, but not limited to, cellular networks, such as fifth generation (5G) and higher generation networks. [Background technology]

[0002] Ranging is the process of measuring the distance and / or angle between two wireless devices as a function of wireless parameters (e.g., signal quality, channel conditions, round trip time, etc.). In wireless systems, the accuracy of the ranging measurement may be directly correlated to the link quality of the wireless channel used, the tuning of the ranging procedure used, or the antenna design, and the hardware capabilities of the used device in terms of energy and computational resources. In addition, the power consumption of the ranging procedure may be directly correlated to the operation frequency, duty cycle, and repetition of messages from one device to the ranging service of another device. Due to such direct correlation with dynamic system parameters, the accuracy and power consumption of ranging in wireless devices may be unpredictable and are often negatively affected. Especially when the ranging measurements are used to derive the location coordinates (e.g., geographic coordinates) of the device, the accuracy of the ranging service is very important in determining the accurate location coordinates. Summary of the Invention [Problem to be solved by the invention]

[0003] Wireless standards provide standardized techniques to support peer-to-peer ranging, and requirements are specified by multiple use cases, for example as described in 3GPP specification TR22.855 "Study on Ranging-based Services". However, there remain open challenges to improving location-based services using specific ranging constellations. These include, for example, location accuracy in deep indoor environments due to poor signal quality and cellular coverage, ranging accuracy in outdoor environments due to channel variability and reflection characteristics, calibration errors due to range bias and ranging errors, power consumption of the ranging service due to transmission and reception of multiple packets for a single distance / coordinate measurement, and power consumption of the location service due to the technology the network uses for the location service.

[0004] As discussed in RWS-210491 ("Views on study of sidelink based positioning in Rel.18"), it is desirable to use sidelink resources to perform ranging and leverage these measurements to improve positioning accuracy.

[0005] However, when combining ranging and location services, it is necessary to address the calibration of the ranging service and / or the reduction of power consumption, more specifically, how to (self-)determine the need for calibration of the ranging service, how to determine the reliability of the ranging measurements (e.g., distance, angle), and / or how to optimize the choice between ranging and location services at a given time.

[0006] An object of the present invention is to improve calibration and power management for combined ranging and location based services. [Means for solving the problem]

[0007] This object is achieved by an apparatus according to claims 1 and 11, a network device according to claim 14, a system according to claim 15, a method according to claims 16 and 17 and a computer program product according to claim 18.

[0008] According to a first aspect, there is provided an apparatus (e.g., in a mobile communications device (e.g., UE)) for providing a location estimate for a target mobile device in a wireless network, the apparatus comprising: determining a timing difference between the target mobile device and an anchor device of a ranging constellation used to support positioning services provided within the wireless network; Upon detecting that the timing difference exceeds an upper threshold a calibration procedure is initiated. According to a second aspect, an apparatus is provided (e.g., in a mobile communications device, an access device, or a core network device or function) for providing a position estimate for a target mobile device in a wireless network, where the apparatus monitors resource capabilities of at least one of a plurality of anchor devices of a ranging constellation and, based on the monitored resource capabilities, reduces power consumption by selecting at least one of the plurality of anchor devices, or limiting position determination including ranging and positioning services to ranging services, or limiting ranging services to a particular direction or distance.

[0009] According to a third aspect, there is provided a network device including an apparatus of the first aspect or an apparatus of the second aspect.

[0010] According to a fourth aspect, there is provided a system including at least one first network device including an apparatus of the first aspect, and at least one second network device including an apparatus of the second aspect.

[0011] According to a fifth aspect, there is provided a method of obtaining a location estimate for a target mobile device in a wireless network, the method comprising: determining a timing difference between a target mobile device and an anchor device of a ranging constellation used to support a positioning service provided within the wireless network; and initiating a calibration procedure upon detecting that the timing difference exceeds an upper threshold.

[0012] According to a sixth aspect, there is provided a method of obtaining a location estimate for a target mobile device in a wireless network, the method comprising: monitoring a resource capability of at least one of a plurality of anchor devices of a ranging constellation; and reducing power consumption by selecting at least one of the plurality of anchor devices based on the monitored resource capabilities, limiting location determination including ranging and positioning services to ranging services, or limiting ranging services to a particular direction or distance.

[0013] Finally, according to a seventh aspect there is provided a computer program product comprising code means for generating the steps of the above methods according to the fifth or sixth aspect when executed on a computing device.

[0014] Thus, a management entity (e.g., a base station, a user device, or a core network device / function) initiates calibration and / or selection of one or more UEs and anchor UEs of a ranging constellation to support ranging-based positioning services. In addition to improving positioning and ranging accuracy, the ranging constellation also helps reduce power consumption of the mobile device by combining ranging and location services. The need to perform a calibration procedure is determined, and the calibration procedure is configured, for example, to improve accuracy and reduce power consumption. Sidelink resources are grouped as ranging constellations. The ranging constellations are managed with respect to the process of determining anchor nodes in the ranging constellation and configuring the anchor nodes to operate as anchor heads, nodes, and members in the constellation based on available information. The ranging constellations are also managed with respect to how to maintain and manage the integrity of the ranging constellation if the members of the ranging constellation are constantly changing, or how to manage the ranging constellation if it is widely distributed geographically.

[0015] The devices that compose a ranging constellation may be selected based on a set of one or more device criteria. Selection criteria may include support for a satellite-based positioning system (e.g., GPS, GNSS, etc.), whether the device's location is known, specific ranging capabilities, existing membership in other ranging constellations, distance to a particular reference point (e.g., a nearby access device), speed, and / or a determination of whether the device is fixed or moving. The formation of the ranging constellation and the selection of its members may be performed by a managing entity.

[0016] Ranging services, location services, and / or ranging-based positioning services may be provided by a network other than the wireless network that collects the ranging measurements. It may be a third-party application that calculates the location based on these measurements. Furthermore, the geographic area of ​​the positioning service may depend on the capabilities of the anchor device and / or the characteristics of the environment in which the anchor device is configured. It need not be known to the network in advance and may be optionally configurable.

[0017] According to a first option, which may be combined with any of the first to seventh aspects above, a synchronization signal may be received from the anchor device and the timing difference may be determined based on the synchronization signal, thereby allowing an available synchronization signal transmitted or broadcast from the anchor device to be used for the calibration process.

[0018] According to a second option, which may be combined with the first option or any of the first to seventh aspects above, a calibration procedure may be performed in which the received synchronization signal is used to adjust at least one communication parameter, thereby adjusting the communication parameter to the received synchronization signal and providing a local calibration process.

[0019] According to a third option, which can be combined with the first or second option or any of the first to seventh aspects, the determined timing difference may be corrected using a timing correction determined based on the synchronization signal, thereby achieving local calibration by applying the timing correction to correct the local timing before requesting the ranging service.

[0020] According to a fourth option, which can be combined with any of the first to third options or any of the first to seventh aspects above, the timing corrections may be periodically updated during the ranging measurements until the determined timing error reaches a lower threshold level, thus providing a continuous adaptive local calibration during the ranging service.

[0021] According to a fifth option, which may be combined with any of the first to fourth options or any of the first to seventh aspects above, a ranging request may be sent to the anchor device, an acknowledgement may be received from the anchor device in response to the ranging request, and a timing difference may be calculated based on a local transmission time and a reception time of the ranging request or the acknowledgement, whereby a calibration procedure may be triggered via the ranging request, and the local timing value obtained from the initiated handshake process may be used for the calibration.

[0022] According to a sixth option, which may be combined with any of the first to fifth options or any of the first to seventh aspects above, a threshold level may be provided that is configurable by the ranging service of the ranging constellation or by a user or application of the target mobile device, thereby enabling adaptive control of the initiation of the calibration procedure, for example based on a desired accuracy and / or power optimization.

[0023] According to a seventh option, which may be combined with any of the first to sixth options or any of the first to seventh aspects, a ranging request may be sent to the anchor device, a round trip time taken for the ranging request to be acknowledged by the anchor device may be measured, and a ranging distance may be calculated based on the measured round trip time, provided that the timing difference does not reach a threshold level. Thus, the ranging process may be controlled according to the determined calibration requirements.

[0024] According to an eighth option, which may be combined with any of the first to seventh options or any of the first to seventh aspects, the determined timing difference may be transmitted to the anchor device and a timing synchronization procedure may be requested via a sidelink interface, thereby controlling the anchor device to initiate a synchronization procedure based on the determined timing difference at the target mobile device.

[0025] According to a ninth option, which may be combined with any of the first to eighth options or any of the first to seventh aspects above, the anchor device may be requested to adjust its synchronization schedule based on the determined timing difference, so that the timing at the anchor device can be synchronized with the local timing of the target mobile device.

[0026] According to a tenth option, which can be combined with any of the first to ninth options or any of the first to seventh aspects, an anchor device of the ranging constellation located at a distance greater than a minimum distance from the target mobile device may be selected to improve ranging accuracy, thereby reducing energy consumption while maintaining or improving the accuracy of the distance measurement.

[0027] According to an eleventh option, which may be combined with any of the first to tenth options or any of the first to seventh aspects above, the ranging constellation may be configured to stop the calibration procedure with the first network device (e.g., the target mobile device) upon completion of the requested ranging service or after a configurable timeout value has elapsed. Thus, power consumption can be reduced by performing the calibration procedure only during the ranging service.

[0028] It should be noted that each of the above apparatuses may be implemented based on individual hardware circuits having separate hardware components, integrated chips, or chip module configurations, or based on signal processing devices or chips controlled by software routines or programs stored in memory, written onto a computer-readable medium, or downloaded from a network such as the Internet.

[0029] It is to be understood that the apparatus according to claims 1 and 11, the network device according to claim 14, the system according to claim 15, the method according to claims 16 and 17, and the computer program product according to claim 18 may have similar and / or identical preferred embodiments, in particular as set out in the dependent claims.

[0030] It is to be understood that a preferred embodiment of the invention can also be any combination of the dependent claims or the above embodiments with the independent claims.

[0031] These and other aspects of the invention will be elucidated and elucidated with reference to the embodiments described hereinafter. [Brief description of the drawings]

[0032] [Figure 1] FIG. 1 illustrates diagrammatically different concepts for providing ranging services to mobile devices with or without network coverage. [Diagram 2] FIG. 2 shows a schematic diagram of different directions in a spherical coordinate system. [Diagram 3] FIG. 3 shows a schematic timing diagram of data transmission between a transmitter and a receiver to illustrate the concept of round trip time. [Figure 4] FIG. 4 shows a schematic diagram of the concept of arrival angle based on phase difference. [Diagram 5] FIG. 5 illustrates generally a block diagram of a wireless system providing ranging and / or positioning services according to various embodiments. [Figure 6] FIG. 6 illustrates a schematic of a network architecture in which a mobile terminal approaches a ranging constellation of mobile terminals and is assisted by a ranging service for location coordinates, according to various embodiments. [Figure 7] FIG. 7 illustrates a schematic diagram of a signaling and processing diagram for a ranging-based positioning service, according to various embodiments. [Figure 8] FIG. 8 illustrates generally a signaling and processing diagram of a process for identifying the need for calibration according to one embodiment. [Figure 9] FIG. 9 illustrates generally a signaling and processing diagram of a calibration process according to an embodiment. [Figure 10] FIG. 10 illustrates generally a signaling and processing diagram of a centralized calibration process according to one embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0033] Embodiments of the present invention are described based on ranging and / or positioning (also called "location") services of a cellular network, where for example 4G network elements may be incorporated in a proposed 5G solution. Furthermore, at least some of the following embodiments are described based on 5G New Radio (NR) radio access technology.

[0034] Throughout this disclosure, the term "wireless network" refers to the entire network system (e.g., 4G or 5G system) including communication devices (e.g., UEs), radio access networks (RANs), and core networks (CNs). Additionally, the abbreviations "eNB" (4G terminology) and "gNB" (5G terminology) refer to access devices such as cellular base stations or WiFi access points. eNB / gNBs are part of the RAN, which provides an interface to functions in the CN. RANs are part of wireless communication networks. RANs implement radio access technologies (RATs). Conceptually, RANs exist between communication devices such as mobile phones, computers, and remote control machines, and provide connectivity to their CNs. CNs are the core part of the communication network, providing various services to customers interconnected through the RANs. More specifically, they transmit communication streams through the communication network and possibly other networks. 3GPP specifications 23.303, 23.304, 24.334, 24.554 for 4G and 5G networks define so-called ProSe (proximity service) features that allow, for example, the connection of cellular communication devices (e.g., UEs) that are outside the coverage range of an access device (eNB). One particular feature is called ProSe UE-to-network relay, or relay UE. A relay UE is a communication device that helps another out-of-coverage (OoC) UE to communicate with an eNB (i.e., access device) by relaying application and network data traffic in both directions between the OoC UE and the eNB. The local communication between the relay UE and the OoC UE is called D2D communication, or sidelink communication or PC5 communication. The abbreviation "PC5" stands for the interface for sidelink communication defined by ProSe.Furthermore, the abbreviation "UL" is used for the uplink direction from a communication device (e.g., UE) to an access device (e.g., eNB, gNB), the abbreviation "DL" is used for the downlink direction from an access device (e.g., eNB, gNB) to a communication device (e.g., UE), and the abbreviation "SL" is used for sidelink communication between two or more communication devices (e.g., UEs).

[0035] When a relay relationship is established, the OoC-UE is connected via a relay UE and takes the role of a "remote UE". This situation means that the remote UE has an indirect network connection to the CN, as opposed to the normal case of a direct network connection (see 3GPP specification TS22.261 v16.10.0).

[0036] Furthermore, 3GPP specifications TR23.733 v15.1.0 and TR36.746 v15.1.1 provide research on architecture enhancements, for example allowing IoT devices (in the role of remote UEs) to operate at very low power by connecting to a wider network using relay UEs. Relay UEs are physically very close and can be reached using very low power transmissions. This work also includes improvements to the security, speed, and stability of ProSe. These extensions of ProSe are called enhanced ProSe ("eProSe").

[0037] ProSe can also be used for direct communication between two UEs. For further radio level details regarding ProSe, V2X, and sidelink communications, please refer to 3GPP specifications TR37.985, TS38.300, and TR38.836.

[0038] Ranging can be defined as the process of measuring the distance and / or the relative direction angle between two wireless devices in three-dimensional space. The first mentioned specification TR22.855 "Study on Ranging-based Services" defines ranging-based services as applications that exploit the distance between two UEs and / or the direction from one UE to another. These ranging-based services are assumed to be supported with or without network coverage. After the distance and direction angle measurements, the next most important measurement is whether two wireless devices are in direct line of sight or not, since this is important in relation to many use cases where UEs interact with each other when they are in line of sight, e.g. in the same room.

[0039] In this specification, the term "ranging reference signal" is used to denote a signal used to determine the distance and / or angle between two devices that may be connected via a device-to-device connection (e.g., using a sidelink and / or PC5) rather than an infrastructure connection (e.g., using a Uu interface). The ranging reference signal may be a position reference signal and / or a sounding reference signal, or other signal that may be used to determine the distance and / or angle between the devices (e.g., a signal used for round trip time (RTT) measurements), and may use resources (that may be configured or provided by the access device) for device-to-device (e.g., sidelink) communication / detection and / or resources specifically reserved for transmitting reference signals or other signals that may be used to determine the distance and / or angle between the devices.

[0040] In this specification, the terms "ranging-capable device" and "ranging-capable UE" are used to denote a device having a minimum set of components, subsystems, and / or functions to perform or support distance and / or angle measurements between itself and another device (e.g., using time difference of arrival, round trip time, carrier phase, or other measurements / techniques). This set of components, subsystems, and / or functions need not be enabled all the time, but may be enabled / triggered on demand (e.g., by request from another device or network function). Also, the components, subsystems, and / or functions may not necessarily be authorized to be used to perform distance measurements. Thus, the terms "ranging-capable device" and "ranging-capable UE" may also be interpreted as being capable of performing and authorized / enabled to perform distance and / or angle measurements between itself and another device. Also, in sentences where the word "capable" is used, it may also be interpreted / restricted as being enabled and / or authorized.

[0041] Ranging capabilities may vary from device to device. For example, not all devices are capable of calculating angles, as this requires multiple antennas. A device's ranging capabilities (which may be interchangeable as part of the discovery process) can be used to determine what the device is capable of and the measurements it can perform. Note that angle calculation may need to be an explicit capability, rather than being based solely on the ability to declare the number of antennas. Having only two or more antennas does not automatically imply that the device can calculate angles. Angle calculation may further require sensors (e.g., magnetometers, gyroscopes, accelerometers) to derive orientation and / or angle relative to a reference point such as magnetic north, and / or an angle / orientation calibration mechanism. Angle may also indicate an elevation difference, potentially using a reference elevation (e.g., meters above sea level and / or air pressure, floor information, terrain elevation data for the device location, etc.), and an elevation calibration mechanism.

[0042] Distance / angle / position calculation technology 1A-1C illustrate diagrammatically different concepts of providing ranging services based on the distance and / or direction (D) between two mobile devices 10, 12 with or without network coverage. The dotted oval shows a perspective view of a circular coverage area around an access device (e.g., gNB) for accessing a 5G cellular network.

[0043] In FIG. 1A, a first UE 10 is located within the coverage area of ​​an access device 20, while a second UE 12 is located outside the coverage area and therefore does not have network coverage.

[0044] In FIG. 1B, both the first UE 10 and the second UE 12 have no network coverage.

[0045] In FIG. 1C, both the first UE 10 and the second UE 12 are located within the coverage area of ​​the access device 20 and therefore have network coverage.

[0046] FIG. 2 shows a schematic diagram of different directions in a spherical coordinate system.

[0047] Distances and angles between multiple sets of UEs (e.g., observer UEs (O-UEs) and target UEs (T-UEs)) can be visualized in a two-dimensional (2D) plane within a three-dimensional (3D) sphere, as shown in Figure 2. The horizontal direction of the target UE (i.e., azimuth angle (Az)) is the angle between the reference direction (RD) and a line from the observer UE to the target UE projected onto the same plane as the target reference direction perpendicular to the zenith direction (Z). The elevation angle of the target UE (i.e., elevation angle (El)) is the angle above the horizontal plane, i.e., the angle formed between the horizontal target reference direction and the direction from the observer UE origin to the target UE.

[0048] As explained in the ranging study by Mario H. Castaneda Garcia et al., “A Tutorial on 5G NR V2X Communications” (DOI 10.1109 / COMST.2021.3057017), a ranging measurement between two UEs can yield two parameters: the distance in meters between the two UEs, and the angle in degrees by which the target UE is elevated in a 3D plane from the observer UE.

[0049] There are several use cases that require a range accuracy within 10 cm (i.e., time measurement accuracy range of less than nanoseconds) with an effective ranging distance of 20 m, and a maximum tolerance of ±2° in the horizontal and vertical planes with a coverage range of angle of arrival (AoA) of -45° to +45° relative to the reference direction of the ranging device. In some use cases, a local coordinate system is proposed for the ranging UE, where the measured distances and angles from the ranging service are converted to location coordinates. UEs involved in ranging are expected to move with various speeds (e.g., 1 m / s to 10 m / s), multiple ranging operations can be performed simultaneously between multiple UEs in a given area, and a UE can perform multiple ranging operations simultaneously with other UEs present in the area.

[0050] So-called "peer-to-peer ranging" can be performed in a number of ways, including but not limited to:

[0051] i. Two-way ranging. This is a process in which two devices A and B transmit data packets and acknowledgement packets to each other. This technique takes into account the time delays caused by natural radio signal propagation, and the processing delays at device B (i.e., the time it takes device B to retransmit the packet to device A). At device A, the one-way flight time is calculated as half the difference between a) the time it takes device A to transmit a packet and receive the next packet from B, and b) the time it takes device B to receive a packet from A and send a response packet back to A. To allow A to calculate the time it takes B, device B may include information in the response packet. Then, at device A, the one-way flight time can be used to calculate the distance between the two devices A and B. Device B can perform the same procedure as device A to calculate this distance as well. This technique takes into account the processing delays of two successive packet transmissions, and does not require the clocks of the two devices to be synchronized with each other, since the distance can be calculated at both devices simultaneously.

[0052] ii. One-way ranging. This is a process in which at least one packet is transmitted between a sending wireless device A and a receiving wireless device B. These devices are mutually synchronized by a common clock source. The time of flight is measured as the difference between the receive time at device B and the transmit time at device A. Device A may include a timestamp of its transmit time in the data packet so that device B can calculate this time difference. The ranging accuracy depends on the accuracy of the clock synchronization achievable between the two devices.

[0053] Peer-to-peer ranging operations may depend on multiple parameters of wireless communication, such as clock time synchronization between devices, the communication path over which the signal is transmitted (e.g., line-of-sight (LOS) or non-line-of-sight (NLOS)), antenna characteristics, operating frequency, transmit power, and receiver sensitivity of the radio waves. These parameters are also important for wireless communication in general, and there are many standardized techniques to achieve the best communication performance for a given radio. For example, in 3GPP, the sidelink radio resource protocol described in specification 36.331 v16.4.1 ensures highly accurate clock time synchronization between two sidelink UEs operating in multiple in-coverage and out-of-coverage scenarios.

[0054] Positioning can be defined as the process of determining the location coordinates of wireless devices, such as mobile phones, wearable devices, and IoT devices, according to a location coordinate system. After determining the location coordinates of the device, the location coordinates may be placed on a map using a mapping function. Positioning is usually distinguished between absolute positioning (i.e., determining geographic coordinates (location coordinates) according to a standardized geographic coordinate system) and relative positioning (determining coordinates relative to a reference point (e.g., using a local coordinate system) and / or angles and distances). Examples of how to express absolute or relative positions are described in 3GPP specification TS 23.032. Typical examples include satellite-based location services (e.g., Global Positioning System (GPS) or Global Navigation Satellite System (GNSS)). In this service, the location coordinates of the device are calculated using at least three of a large number of satellites belonging to a Medium Earth Orbit (MEO) constellation, using well-known processes such as triangulation and trilateration. The satellites act as clock synchronization sources, and the communication delays of the transmitted packets are used to estimate the location coordinates. These coordinates can be used by any third party mapping tool (e.g., OpenStreetMap) to pinpoint the location of the device on a map of the area. Also available are several indoor positioning technologies based on radio frequency technologies such as Bluetooth, UWB (UltraWideBand), or WiFi that can identify / determine the coordinates of tags emitting radio frequency (RF) in indoor environments. The locations of these tags may be mapped onto an indoor floor plan using indoor coordinates estimated based on RF propagation characteristics such as time delay, multipath reflections, and received signal strength measured using RF communication between the tags and anchor nodes placed at known locations in the building.

[0055] The positioning techniques used to obtain the coordinates of the device's current location can be accomplished in a number of ways, but typically involve triangulation and / or trilateration based on a set of measured distances and / or angles between the device and a set of other devices or reference points. Distances and angles can be determined using a variety of techniques, including round trip time (RTT), time of flight (ToF), time difference of arrival (TDoA), angle of arrival / departure (AoA / AoD), and / or combinations of these.

[0056] Round Trip Time (RTT) defines the duration from when a data packet is sent by a transmitter (Tx, e.g. access point / device) to when the same data packet is received and acknowledged by a receiver (Rx, e.g. mobile phone / device), i.e. when the transmitter receives the acknowledgement. Since data packets travel at the speed of light (approximately 3.3ns / m) in the air medium, the time it takes for a data packet to travel in the air is proportional to the actual distance between Tx and Rx. In cases where the internal clocks of Tx and Rx are not synchronized, one-way time measurement cannot be based on the difference between the transmit timestamp and the receive timestamp, because it also includes timing errors caused by internal clock drift and uncertain clock offset between Tx and Rx. Since the internal clocks of Tx and Rx are not synchronized, the difference in timestamps when the signal travels in the reverse direction (i.e. from Rx to Tx) is affected by the clock offset in the opposite way to the forward direction (i.e. from Tx to Rx).

[0057] FIG. 3 shows a schematic timing diagram of data transmission between a transmitter and a receiver to illustrate the concept of round trip time.

[0058] In the timing diagram of FIG. 3, time progresses from top to bottom, with the flow of information between a transmitter (Tx) and a receiver (Rx) indicated by respective arrows.

[0059] 3, a data packet (DP) is sent from Tx to Rx at time t1 and is received by Rx at time t2. An acknowledgement (ACK) is sent from Rx to Tx at time t3 and is received by Tx at time t4.

[0060] The round trip time (RTT) can be obtained without knowing the clock offset by simply adding and subtracting four timestamps t1 to t4 as follows: RTT = (t4-t1+t2-t3) Here, t1 is the transmission time, t2 is the reception time, t3 is the transmission time of the acknowledgement, and t4 is the reception time of the acknowledgement.

[0061] The distance D between Tx and Rx can be estimated using the following formula: 2*D=((t4-t1)-(t3-t2))*c where c is the speed of light. It should also be noted that distance estimation based on RTT measurements does not require synchronization between the transmitter and receiver. The single distance calculation can be extended to two- and three-dimensional space to estimate multiple distances, which can be converted to estimated location coordinates (both local and global) if the coordinates of each transmitter are known in advance. Standardized mechanisms that use RTT-based techniques include Fine Timing Measurement (FTM), defined in IEEE 802.11-2016, and Enhanced Cell-ID (E-CID), defined in 3GPP TS 36.133.

[0062] Time of Flight (ToF) corresponds to the duration from when a data packet is transmitted by a transmitter (Tx, e.g., an access point / device) until the same data packet is received by a receiver (Rx, e.g., a mobile phone / device). Note that this method only considers the forward path (i.e., from Tx to Rx) and not the reverse path (i.e., from Rx to Tx). In this case, the internal clocks of Tx and Rx (or multiple Tx and Rx) need to be time-synchronized so that the timestamp of the received packet can be considered correct and the timing errors caused by internal clock drift and uncertain clock offset between Tx and Rx, etc. are corrected. Assuming that Tx and Rx in Figure 3 are synchronized, the distance D between Tx and Rx can be calculated by the following formula: D=(t2-t1)*c where t2 is the timestamp of reception, t1 is the timestamp of transmission, and c is the speed of light. The time of flight can be calculated by Rx knowing the timestamp t1 (e.g., included in the transmitted message or signaled later) and its own measured timestamp t2. The time of flight can also be calculated by Tx knowing the timestamp t2 (e.g., sent later by Rx to Tx) and its own measured timestamp t1. The calculation of a single distance can be extended to two- and three-dimensional space to estimate multiple distances, and if the coordinates of multiple reference devices (whether acting as transmitters or receivers) are known in advance, these can be converted to estimated position coordinates (both local and global).

[0063] The arrival time difference corresponds to the difference in the time stamps at which a data packet is received by multiple clock-synchronized receivers (Rx, e.g., access points / devices that are synchronous position reference stations), which were transmitted by an asynchronous transmitter (Tx, e.g., a mobile phone / device whose location coordinates are to be determined or an asynchronous location tag). Note that the roles may be reversed, e.g., a mobile phone / device may be an asynchronous Rx and an access point / device may be a synchronous transmitter. Note that a single transmission of a data packet by a transmitter is simultaneously received by multiple synchronized receivers located within the coverage area of ​​the transmitter. While a transmitter whose location coordinates are to be determined may not be synchronized with either other transmitters or receivers, it is important that the receivers are clock-synchronized and that their location coordinates are known to a central location server. The central location server receives the arrival time of the data packet from each receiver i=0···N and can calculate the distance difference of any receiver pair (i,j) to a particular transmitter based on the following formula: Δd ij =(d i -d j )=Δt ij *c where c is the speed of light, Δt ij is the difference in arrival time between receiver i and receiver j, d i is the unknown Tx to Rx distance of receiver i, Δd ijis the difference in distance from Tx to Rx for receiver i and receiver j. Calculations can be applied in two-dimensional and three-dimensional space to estimate the distance difference, and the distance difference can be converted to location coordinates (both local and global) if the receiver coordinates are known in advance. Note that the transmitter cannot calculate its own position locally on the device, only a location server can calculate the transmitter's position using a location infrastructure and a network of multiple synchronized receiver nodes. The location server may be located at one of the clock-synchronized receivers. The transmitter's position may be communicated (e.g., to an application, a transmitter, or one or more receivers) via another communication channel or may be fixed in one of the responses from the receiver to the transmitter on the same channel used to transmit the data packet.

[0064] Alternatively or additionally, the receiver may transmit measurements (e.g., time of arrival information) rather than calculated distances or angles to the transmitter or location server, which calculates the resulting distances and / or determines the resulting location coordinates. Some standardized mechanisms that use ToF difference based techniques include Observed Time Difference of Arrival (OTDOA) defined in 3GPP TS 25.305 and TS 36.133, Uplink Time Difference of Arrival (UTDOA) defined in 3GPP TS 25.305, which are typically based on Position Reference Signals (PRS) or Sounding Reference Signals (SRS).

[0065] In addition to time-based distance estimation, the angle of arrival can be derived from the phase information of the RF signal received at the receiver using the antenna array and can be used to estimate the elevation or azimuth angle at which the signal was received. This angle information can be used to determine the direction from which the signal was transmitted.

[0066] FIG. 4 shows a schematic diagram of the concept of arrival angle based on phase difference.

[0067] In the example of Figure 4, the angle of arrival of the input RF signal (indicated by the two diagonal arrows) can be calculated as follows: In principle, a receiver having at least two antennas with different receive phases φ1, φ2 and spaced a distance d apart can determine the phase difference Δφ of the signals received at the receiver and use it to estimate the angle of arrival based on the following equation: Δφ=[φ1-φ2]=2π[(dcosθ1) / λ]+2kπ where θ1 is the angle of arrival to be estimated, k is the wavenumber which can be calculated as k=2πλ, λ is the wavelength of the RF signal which can be calculated as λ=c / f, c is the speed of light, and f is the radio frequency of the signal.

[0068] The angle of arrival of the RF signal at the receiver can be estimated with a simple approach based on the measured phase difference using the following equation: cosθ1=[(Δφ / 2π)-k]*[λ / d]

[0069] In addition to the above approaches, there are several well-known approaches available for calculating the angle of arrival of RF signals, including but not limited to Bartlett beamforming (see MS Bartlett: "Smoothing Periodograms from Time-Series with Continuous Spectra"), Multiple Signal Classification (MUSIC) (see https: / / en.wikipedia.org / wiki / MUSIC_(algorithm)), distortion estimation (J. Capon: "High-resolution frequency-wavenumber spectrum analysis", Proceedings of IEEE, Vol. 57, issue 8), and signal and noise subspace estimation. Other complex AoA estimations may use three or more antennas at the receiver. This allows both angle and distance measurements to be obtained based on RF signals transmitted by asynchronous transmitters with relatively simple hardware and a single antenna, with only one receiver instead of three synchronous receivers. Similarly, if the transmitter uses multiple antennas, the angle of departure of the signal at the transmitter can be identified and used for ranging / location estimation.

[0070] The process of obtaining the location coordinates of a device and locating the device on a map using mapping functions is also provided by the Location Services (LCS) provided in the 3GPP® system. In these services, the base station acts as a synchronization source and the location coordinates of the device are obtained based on radio parameters and special messages using various positioning methods described, for example, in 3GPP® specification TS 23.271 “Functional stage 2 description of Location Services (LCS)” Release 16 for 4G and 3GPP® specification TS 23.273 “5G System (5GS) Location Services (LCS); Stage 2”, Release 17 for 5G.

[0071] The general difference between location-based and ranging services provided by 3GPP systems is that location-based services can measure the geographic coordinates of a device within a cell coverage area (e.g., 1-5 km) with line-of-sight (LOS) to a base station, with good accuracy in outdoor environments where the communication path can be properly modeled and taken into account using channel models for urban and suburban environments, whereas ranging services can measure the distance and / or angle between two devices within a short distance (e.g., 20 m) with good accuracy in outdoor environments and especially in indoor environments where two ranging devices are within line-of-sight (LOS) to each other.

[0072] Combining location and ranging service capabilities may provide a location service with, for example, improved accuracy and improved indoor location estimation. The location and / or ranging service, or a combination thereof, may also be able to verify the consistency / measure accuracy / identify and possibly correct errors in the measured distance, angle, location information (e.g., coordinates), etc., and / or provide the distance, angle, location information to the UE, core network functions, applications, or other location / ranging services, and / or store the distance, angle, location information in non-volatile storage, and / or combine the distance, angle, location information with distance, angle, location information from other sources or obtained from various location / ranging mechanisms.

[0073] Location services may also provide ranging services (and vice versa), for example if the positions of two devices can be observed / determined (e.g. via GNSS) they may be exposed as part of a ranging service that calculates the distance and / or angle between the two devices and allows a device to request the distance and / or angle between itself and another device. Even in such a case, it may be required to perform ranging measurements between the two devices to improve the accuracy of the distance and / or angle between the two devices or to determine the offset from the observed / determined positions.

[0074] The distance to coordinate conversion can be performed, for example, based on ranging measurements that allow a first device A to obtain the distance (d) and angle (tc) to a second device B. If the coordinates of device A are known and its orientation relative to the coordinate system is known, device A can use the distance and angle measurements between device A and device B to obtain the coordinates of device B.

[0075] For example, for geographic coordinates expressed in radians, assume the latitude (lat1) and longitude (lon1) of device A are known. When using a spherical Earth model, the geographic coordinate (lat2, lon2) of device B can be calculated using the following formula: lat2=asin(sin(lat1)*cos(d)+cos(lat1)*sin(d)*cos(tc)) dlon=atan2([sin(tc)*sin(d)*cos(lat1)],[cos(d)-sin(lat1)*sin(lat2)]) lon2=[mod(lon1-dlon+π,2*π)]-π Here, the distance d is expressed as a relative distance equal to the distance measured between A and B divided by the mean radius of the Earth.

[0076] As another example, for a local 2D Cartesian coordinate system used for an area, assume the X and Y coordinates of device A (x1 and y1 respectively) are known. Then the X / Y position coordinates of device B (x2 and y2 respectively) can be calculated using the following formula: x2=d*cos(α)+x1 y2=d*sin(α)+y1 Here, all coordinates and distances d are expressed in meters and angles (α) relative to device B measured by A.

[0077] Alternatively, depending on the accuracy required and the type of coordinate system used in the application, other concepts such as inverse Havershine's rule, degree length, Molodensky's method, and block shift methods can be used to convert distances to coordinates in a coordinate system.

[0078] Current ranging and localization technology can be improved in the following areas:

[0079] i. Location accuracy is highly dependent on signal path loss and degrades with decreasing signal quality in indoor and deep indoor environments where cellular coverage is very poor. Location service accuracy is also reduced in remote outdoor environments where signal coverage is sparse or non-existent due to a limited number of base stations. In such areas, depending on the positioning method used, a longer initial latch time may be required for the trilateration or triangulation of the mobile device (e.g., UE) to ensure that at least three different signals from at least three different base stations are received simultaneously. When a mobile device is moving within such areas of poor coverage, the continuity and reliability of the location service provided by the base station may be significantly impaired, making the service unusable for real-time location tracking.

[0080] ii. The ranging accuracy in outdoor environments depends heavily on the variability of the channel and the reflectivity characteristics of objects around the device performing the ranging operation. In indoor environments, the user of the mobile device (e.g., UE) has considerable control over the environment and surroundings relative to the objects before performing ranging between two devices, whereas in outdoor environments the control over the environment is uncertain and often adversely affects the accuracy of ranging. The movement of the mobile device in outdoor environments can also have a significant impact on the ranging accuracy due to the Doppler effect that may occur in the RF propagation channel. Thus, ranging measurements between two devices in outdoor environments may become unusable due to significant adverse effects in the RF channel.

[0081] The following describes embodiments in which ranging and / or positioning concepts are complemented by using ranging measurements (e.g., distance, angle, altitude) between a transmitter and a receiver, thereby improving positioning accuracy and / or reducing power consumption associated with these concepts.

[0082] In some use cases, it may be necessary to convert ranging measurements into location coordinates. Such conversion allows UEs that do not have positioning services or additional positioning modules available to obtain location coordinates derived from the ranging information. Also, devices with very low positioning accuracy, especially in indoor environments, may benefit from ranging, such as improving positioning accuracy in indoor and / or out-of-coverage environments from hundreds of meters to less than a meter accuracy. Furthermore, accurate positioning and continuous tracking of low-power IoT devices is a requirement of another use case, which allows adaptive delivery of Quality of Service (QoS) to mobile UEs depending on their location, e.g., high bandwidth is provided at location X and only low bandwidth is provided at location Y. Among the identified suitable use cases, there may be a need to form clusters of UEs based on location information in order to provide location-based QoS to groups of UEs.

[0083] It should be noted that throughout this disclosure, wherever the concept of ranging and / or positioning is mentioned, any of the ranging and / or positioning methods listed above, or a combination thereof, or other ranging or positioning methods known to those skilled in the art may be used.

[0084] Ranging Constellation (including its Configuration) FIG. 5 illustrates a schematic block diagram of a wireless system providing ranging and / or positioning services according to various embodiments.

[0085] In one embodiment, as shown in FIG. 5, a ranging constellation (RC) 50 is provided, which is a group of one or more anchor UEs (A-UEs) 14, which are adapted / prepared for one or more device UEs 10 to join the group. A device UE 10 can join the ranging constellation 50, for example, to initiate a ranging procedure or to participate in ranging of other UEs by operating as an additional anchor UE 14. A single distance and / or angle obtained from a ranging procedure may not be sufficient to determine the (absolute or relative) location of a UE. In one example, the ranging constellation 50 may have at least two or more anchor UEs 14, and may determine the location of the device UE 10 by determining the distance and / or angle between the device UE 10 and an anchor UE 14 of the ranging constellation, and may calculate the location using trilateration and / or triangulation using the determined distance and / or angle. If additional information is known or can be determined in advance, such as specific coordinates, whether the devices involved in the ranging are at the same height (e.g., a specific number of meters above sea level, on the same floor) or within the same reference plane, then ranging between the device UE 10 and a single anchor UE 10 in the constellation alone may be enough to determine its relative or absolute position.

[0086] The devices that compose the ranging constellation 50 may be selected based on a set of one or more candidate device selection criteria. The selection criteria may include GPS / GNSS support, whether the device's location is known, specific ranging capabilities, existing membership in other ranging constellations, distance to a particular reference point (e.g., a nearby access device), speed, and / or a determination of whether the device is fixed or moving, or whether the candidate device is within sidelink detection range of another device (e.g., an anchor device). The formation of the ranging constellation and the selection of its members are typically performed by a management entity, but may also be self-configured based on the selection criteria.

[0087] A device UE 10 may be added to or removed from an existing ranging constellation. Similarly, an anchor UE 14 may be added to or removed from an existing ranging constellation. The ranging constellation 50 may be given an identification (e.g., by a management entity) and this identification may be transmitted to each device that joins / constitutes the ranging constellation 50. This identification may also be used during detection of ranging-enabled devices and / or during connection establishment between ranging-enabled devices and / or during message exchange to initiate a ranging session. A ranging constellation may be assigned multiple identifications (e.g., both a unique constellation instance identifier and a constellation type identifier). It should be noted that the addition, removal, and / or joining of a device UE 10 to a ranging constellation does not imply that the device UE 10 needs to have information about all anchor UEs of the ranging constellation or needs to establish a session with all anchor UEs of the ranging constellation. For example, the set of other UEs in the ranging constellation may be known only to the LMF or other management entity. The UEs in the ranging constellation may form a trusted group / domain, whereby UEs that are part of the ranging constellation may share the same / similar group / domain credential or authorization token. This may allow (if necessary) a UE to prove to other UEs in the ranging constellation that it is part of the same ranging constellation if it can provide proof of possession of the group / domain credential or authorization token (e.g., by sending a correct response to an authentication / authorization request or by sending a correctly signed token / message). The shared group / domain credential may be used to protect (e.g., encryption and / or integrity protection) message exchanges between UEs that are part of the ranging constellation. This may include protection of multicast / groupcast messages.UEs that do not have the group / domain credentials cannot decode those messages. In this way, the UE does not need to know directly which other UEs are part of the constellation or which UEs may join the constellation. Alternatively or additionally, the UEs in the ranging constellation may receive authentication information separate from each other UE in the ranging constellation.

[0088] The device UE 10 corresponds to a wireless device requiring ranging and / or positioning services and is also referred to as a target UE. Note that in the description of this and the following embodiments, the terms "device UE" and "UE" are used interchangeably and refer to the same device. Also, the terms position and location are used interchangeably and can be either relative (e.g., coordinates in a reference plane) or absolute (e.g., geographic coordinates).

[0089] Each anchor UE 14 corresponds to a wireless device that provides ranging and / or positioning signals to the UE 10. Additionally, the anchor UE 14 may provide ranging / positioning services to the UE and other anchor UEs.

[0090] It should be noted that device UE10 and anchor UE14 may be mobile phones or any type of connected device and may support Uu and PC5 3GPP interfaces. These devices may be capable of supporting multiple radio access technologies, such as, but not limited to, 2G / 3G / 4G / 5G networks as defined by 3GPP, WiFi spectrum, Bluetooth spectrum, and non-3GPP wireless technologies operating in unlicensed wireless spectrum such as ISM bands. The mobility of device UE10 and anchor UE14 does not affect whether device UE10 can become anchor UE14 or vice versa. In some applications, anchor UE14 may be a fixed device (e.g., smart TV) and mobile device UE10 (e.g., mobile phone) may be allowed to become anchor UE14 while moving or when fixed in one location. Typically, the anchor UE 14 needs to know its location or be able to obtain its location from a location service or provide / determine a reference plane and reference direction for distance / angle measurements using a ranging procedure with the device UE 10, and be able to do this even when it is out of network coverage. The anchor UE's location needs to be relatively stable (e.g., not move or shake much) or at least stable compared to the device UE 10 (e.g., the absolute speed of the ranging UE 14 is less important than the relative speed when both UEs are moving in the same direction, e.g., both UEs are in the same vehicle). The anchor UE is preferably within the network coverage so that it can access location services provided by the core network, obtain its location, maintain synchronization with the network, get approval for ranging procedures, etc. Both the device UE 10 and the anchor UE 14 may have receiving units for receiving ranging reference signals and / or other radio signals used for distance / angle measurements. The receiving units may be able to determine the timing of these signals. Both UEs may also have computation units for calculating / determining distance / angle / positioning measurements (e.g., Reference Signal Time Difference (RSTD), Reference Signal Received Power (RSRP), Rx-Tx time difference between the device UE 10 and the anchor UE 14 and / or between the device UE 10 and the wireless access device (e.g., base station or gNB) 20). The computation units (or another computation unit of the device UE 10 or the anchor UE 14) may be able to calculate distance, angle, or (relative) position based on these distance / angle / positioning measurements (possibly augmented with data from other sensors, e.g., barometric pressure sensors) and / or distance / angle / positioning measurements received from other devices (possibly augmented with data from other sensors, e.g., magnetic sensors). Additionally, the device UE 10 and anchor UE 14 may have a transmission unit for transmitting signals used for distance / angle measurements (e.g., position reference signals or sounding reference signals), and the transmission unit may be able to determine the timing of these signals. The anchor UE may have a known / fixed location and thus may be a position reference unit as described in 3GPP document R2-2109489, and may further transmit this information to the device UE 10 and / or other anchor UEs 14.The device UE 10 and anchor UE 14 may support transmission and reception of signals to enable communication with radio access devices (e.g., as defined in 3GPP® specification TS38.300) and may be able to communicate with the (cellular) core network and its services (e.g., as defined in 3GPP® specification TS23.501), such as location-based services (e.g., as defined in 3GPP® specification TS23.273), using protocols such as LTE Positioning Protocol (LPP) defined in 3GPP® specification TS36.355 or NR Positioning Protocol A (NRPPa) defined in 3GPP® specification TS38.455. Additionally, the device UE 10 and anchor UE 14 may support detection and communication via PC5 / sidelink (e.g., as defined in 3GPP® specifications TS38.300, TS23.287, TS23.304, and TR37.985) with another device UE and / or anchor UE.

[0091] The device UE 10 , the anchor UE 14 and the wireless access device 20 together may form a positioning constellation (PC) 60 .

[0092] Depending on the application and accuracy needs, ranging or sidelink based positioning may be performed between the device UE 10 and one or more anchor UEs 14. For example, simple applications such as coarse ranging may be used by a single anchor UE 14 to indicate a rough range / area. Other applications may require three or more anchor UEs 14 with strict clock synchronization with the device UE 10.

[0093] The ranging constellation 50 includes a set of UEs, e.g., device UE 10 and at least one anchor UE 14, that can perform ranging and support each other in determining geographic location and / or providing relative positioning services (e.g., determining location in a reference coordinate system). In the ranging constellation 50, one of the anchor UEs 14 may be a head or lead anchor UE that manages the set of remaining anchor UEs 14 (e.g., acts as a synchronization source for the other anchor UEs). An anchor UE may also be configured to support a management entity that, e.g., selects, configures, reconfigures, etc., the other anchor UEs 14.

[0094] At least one wireless access device 20 (e.g., a base station or a gNB) is configured to handle a connection from a UE to a core network (CN) 30. At least one wireless access device 20 may also support multiple positioning technologies alone or together with other wireless access devices 20. The wireless access device 20 is responsible for radio resource allocation and scheduling, clock time synchronization, and power control of connected devices, etc.

[0095] The wireless access device 20 may also provide positioning signals and provide (access to) positioning services to devices in the ranging constellation 50. The positioning constellation 60 includes a set of at least one wireless access device 20 (possibly in combination with a positioning service in a core network such as an LMF) that provides positioning services to at least one device UE 10 or anchor UE 14. The device UE 10 or anchor UE 14 may not always be connected to the wireless access device 20, i.e., out of coverage, but the device UE 10 or anchor UE 14 may have previously connected to a positioning service related to the positioning constellation 60 to obtain its position and may have received a position from a management entity (e.g., an installer UE). If the anchor UE subsequently goes out of coverage, it may still transmit ranging signals and / or location information without being connected to the wireless access device 20.

[0096] Furthermore, the core network (CN) 30 provides network functions to control the access network and to manage the UE devices 10 and anchor UEs 14 that subscribe to and are served by the access network. For example, the core network may be a 5G core network. The core network 30 may include a number of network functions, including an access and mobility management function (AMF) 32 configured to manage access and mobility of subscribed UEs, a location management function (LMF) 34 configured to manage positioning services provided to the UEs 10 and anchor UEs 14, a ranging management function (RMF) 36 configured to manage ranging services between the (ranging) UEs 10 and anchor UEs 14, and a network publishing function (NEF) 38 that enables application functions (AFs) 40 to connect to the core network 30.

[0097] It should be noted that in the described embodiment, a network controller device may perform the role of the core network 30. It should also be noted that the LMF 34 or RMF 36 may include or be connected to a set of services / functions (e.g., a Gateway Mobile Location Centre (GMLC)) that together may be responsible / capable of identifying, verifying, providing, and / or storing a set of location, distance, angle, coordinates, and other related information for location and / or ranging services. Additionally or alternatively, the set of services / functions may together be responsible / capable of managing / configuring / operating a set of location and / or ranging services, and / or combining the distance, angle, location information with distance, angle, location information obtained from other sources or various location / ranging mechanisms. The term LMF or RMF refers to such services / functions or combinations thereof. The LMF and RMF may also be considered as location services, ranging services, or a combination of location services and ranging services. The application functions 40 may be third party applications that may be interested in leveraging the services offered by the core network 30 and the wireless connectivity provided to the UE 10 and / or anchor UE 14 .

[0098] According to various embodiments, a management entity is provided that forms a ranging constellation 50 and configures one or more UEs as anchor UEs 14 to support ranging services, location services, and / or ranging-based positioning services (i.e., a combination of ranging and location services capabilities). In addition to improving location and ranging accuracy, the ranging constellation 50 also helps reduce power consumption of at least the involved UEs 10 by combining ranging and location services.

[0099] More specifically, location accuracy can be improved by simple ranging measurements between devices, either locally or centrally initiated and / or coordinated. By way of example, this can be achieved by using ProSe detection messages, and / or carrier phase based ranging / positioning techniques, and / or ranging / positioning signals transmitted in a combination of FR1 frequency ranges (e.g., low / mid bands, typically up to 7.125 GHz) and FR2 frequency ranges (e.g., mmWave bands, typically 24 GHz and above).

[0100] The core network 30 (e.g., a network controller device), together with the radio access devices 20 (e.g., base stations or gNBs), may support ranging and / or positioning services required by one or more device UEs 10 and provided by one or more anchor UEs 14 via a management entity. The management entity may typically support one or more of the following: providing a user interface that allows a user to select and (re)configure a set of UEs to form a ranging constellation and / or to manage ranging and / or location procedures and / or ranging and / or location services, e.g., to configure requirements and parameters of ranging procedures / services and / or location procedures / services, including but not limited to: The ranging / positioning method used (e.g. RTT-based, TDOA-based, AoA / AoD-based), The radio access technology used (e.g. 3GPP® LTE, 3GPP® 5G NR, WiFi®, Bluetooth®, UWB, etc.); The bands to be used (including whether they will use unlicensed or licensed spectrum); the bandwidth used; Minimum / maximum / default measurement time and / or ranging reference signal / measurement timing, the minimum / maximum / default transmit power to use, - the desired / minimum required accuracy of the distance measurement, The size of the constellation (e.g. number of devices, identities of the devices involved, area information, maximum distance), Configuration of the constellation (e.g., known positions and / or initial position estimates and / or estimated distances / angles of one or more devices that compose the constellation); Area map, The coordinate system to be used (including which device or anchor point to use as the primary reference point / center), the sampling frequency of the ranging and positioning measurements, Providing, including credentials (e.g., security keys, IDs) to be used during the detection and / or ranging procedures; - providing an intermediary / proxy configuration function that allows a network entity (e.g. location / ranging management function), an access device (e.g. base station), or an application function (e.g. via a network publishing function) to select and (re)configure a set of UEs to form a ranging constellation, and / or a user interface that allows remote management of ranging and / or location procedures and / or ranging services and / or location services (e.g. configuring the requirements and parameters of ranging procedures / services and / or location procedures / services as described in the above items). The configuration by the network entity may be performed directly (e.g. through a set of messages as part of a configuration protocol) or indirectly (e.g. through a set of policies / rules that the management entity can use to determine how to determine / select an anchor UE, or how to configure the parameters for performing ranging, etc.); - Collect ranging related information from UEs in the ranging constellation (e.g. device identification, ranging capabilities, configuration parameters used for ranging) and send it to the ranging service or location service and / or store it in non-volatile storage. - Collect ranging results (e.g., distance, angle, relative or absolute coordinates) and / or ranging measurements (e.g., round trip time) from UEs in the ranging constellation and transmit them to a ranging or location service and / or store them in non-volatile storage. - Collect information about ranging devices detected by the UEs of a ranging constellation (e.g., detected device identification information, detected ranging capabilities) and / or ranging results (e.g., distance, angle, relative or absolute coordinates) and / or ranging measurements (e.g., round trip time) from a set of UEs and determine whether the set of UEs forms a valid ranging constellation.

[0101] A management entity may be one of the following: - functionality provided by the UE (e.g., anchor UE 14 or installer UE) that allows the ranging constellations, ranging and / or location procedures and / or ranging / location services to be managed manually by a user and / or remotely by a network entity (e.g., a location service to which the anchor UE is in communication connectivity) (e.g., configuring the requirements and parameters of the ranging procedures / services and / or location procedures / services as described above); - users or applications communicatively connected to the core network 30 (e.g. a network controller device) via, for example, the Network Publishing Function 38, and / or the Location Management Function 34, and / or the Ranging Management Function 36, and / or other core network functions that enable managing ranging constellations and / or ranging and / or location procedures / services (e.g. configuring the requirements and parameters of ranging procedures / services and / or location procedures / services as described above); a selected one of the radio access devices 20 and / or the core network 30 (e.g. a network controller device or a visiting core network), which, e.g. after being configured by a Location Management Function 34 and / or a Ranging Management Function 36 (operated by the home core network), is capable of (automatically) managing the ranging constellations and / or ranging and / or location procedures of a set of UEs connected to it and / or the ranging and location services it provides to or is provided by the set of UEs connected to it, or - A Location Management Function 34 and / or a Ranging Management Function 36, either inside or outside the core network 30, that may manage ranging and / or location procedures / services (e.g. configure the requirements and parameters of ranging procedures / services and / or location procedures / services and / or configure ranging constellations) based on operator-managed default operating settings, policies, a location database, historical measurement data, artificial intelligence models, possibly in cooperation with core network functions such as a Network Data and Analysis Function (NWDAF, e.g. to determine device density, number of devices typically registered at a particular time, etc.), or a User Data Management (UDM, e.g. for subscription related data), and / or a Policy Control Function (PCF, e.g. for policy related data).

[0102] The location management function 34 and / or ranging management function 36 or other management entities may configure one or more devices UE 10 and / or one or more anchor UE 14 and / or wireless access devices 20 (management entities) based on the requirements and parameters of the ranging and / or location services (e.g., provided through a network publication function). The configuration may be performed by sending secure messages to the respective device UE 10 and / or anchor UE 14 and / or access device 20 via the PCF or AMF or directly from the location management function or ranging management function when a connection with the access device or core network function (e.g., AMF or location / ranging management function) is established, when a configuration update request is received, and / or when a request to start ranging and / or position estimation is received from one of the involved devices. For this, the device UE 10 and / or anchor UE 14 may need to support a protocol for configuration of the ranging procedure / service (e.g., an extension of the LTE Positioning Protocol (LPP) defined in 3GPP specification TS 36.355). If one or more UEs in the ranging constellation are out of coverage or not directly connected to or managed by the ranging / location management function, the configuration may be provided or forwarded to these UEs by the in-coverage UEs (i.e. partial coverage situation where at least one of the UEs in the ranging constellation is in coverage) or provided / forwarded by a management entity (e.g. supported by a (head) anchor UE, which may operate out of coverage).

[0103] The configuration of requirements and parameters may be performed in the form of a set of policy rules (e.g., provided through an RRC or PCF policy container), which may define a set of conditions (e.g., conditions defining the minimum measurement signal strength at which ranging measurements can be made on a particular frequency) based on which the device determines which configurations / methods / parameters / values ​​to apply.

[0104] In a further example related to the configuration of the device to enable ranging, the configuration of the device UE 10 by the management entity may be achieved by assigning security keying material and ProSe discovery information as described in 3GPP specifications TS33.303 and TS33.305. In particular, a set of discovery user confidentiality keys (DUCK), discovery user integrity keys (DUIK), and / or discovery user scrambling keys (DUSK) may be assigned to achieve integrity protection, scrambling protection, and / or confidentiality protection. The device UE 10 may also have an identifier that identifies, for example, a ranging application. These parameters may be used in combination with discovery messages to enable devices capable of performing ranging with each other to discover each other. The configuration / parameters related to the ranging constellation 50 may not be static and may change over time. In one example, the wireless access device 20 may be communicatively connected to the device UE 10 and / or the anchor UE 14 (possibly in combination with ranging and location services). The device UE 10 may report its device capabilities and application requirements to the RMF 36 and / or LMF 34 or other management entity (e.g., via the radio access device 20 or via another / head anchor UE that may be connected to the radio access 20). The anchor UE 14 may report its current configuration and information about the current status / progress of the members of the ranging constellation 50 (e.g., number of devices, identity information, capabilities, estimated location, estimated speed / mobility, information about battery level / capability, information about resource capacity, or information about which devices are in coverage and which are out of coverage) directly to the RMF 36 and / or LMF 34 or other management entity (e.g., via the radio access device 20) or via another / head anchor UE that may be operating the management entity or may be connected to the RMF 36 and / or LMF 34 or other management entity (e.g., via the radio access device 20).The RMF 36 and / or LMF 34 or other management entity may set policies in the device UE 10 and / or anchor UE 14 that determine parameters for performing ranging, ranging services, and / or location services. These parameters may be based on received (latest) information about the ranging constellation. For example, if information about the current status / progress of the constellation indicates that the number of available anchor UEs of the constellation has decreased since the ranging constellation 50 was established / determined (e.g., because several anchor UEs have been deactivated or moved too far away from other anchor UEs in the constellation), the parameters of the ranging procedure or ranging / location services may be adjusted to reflect the new situation and reconfigured / updated on each device involved in the ranging constellation 50 and / or device UE 10 that may utilize the ranging constellation 50. If the number of available anchor UEs for a constellation (e.g., within an area previously identified as covered by a ranging constellation) is found to be insufficient, the constellation may be discarded and information about and / or configuration parameters relating to the constellation may be deleted from the device UE 10 and / or anchor UE 14, and may also be deleted from the management entity.

[0105] <<Beginning of details regarding calibration of ranging constellations (specific to this application)>> According to various embodiments, a mobile user device or application (e.g., device UE 10) or a management entity such as LMF 34 or RMF 36 may determine if the proposed ranging system needs to be calibrated and initiate or trigger the setting of a configurable threshold for the timing error, e.g., to improve the accuracy of the ranging service. This may be done by the ranging service, which may analyze the configuration of the mobile user device or application or management entity against the desired ranging accuracy, or may be done manually by the user via the mobile user device or application or management entity.

[0106] In one embodiment, the device UE 10 may send a ranging request to an anchor UE 14 belonging to the ranging constellation 50 and measure the round trip time it takes for the ranging request to be acknowledged by the anchor UE 14. Based on this, the device UE 10 may calculate a timing error locally on the device and determine that a timing calibration is required, for example, if the timing error exceeds a pre-configured threshold. If the calculated timing error is less than the threshold, the same timing measurements obtained by the device UE 10 may be used to calculate the ranging distance.

[0107] In one example, the mobile device UE10 can correct the timing error by performing a calibration procedure, in which the mobile device UE10 can correct the timing error using an internal clock and a specific synchronization signal generated and transmitted by the anchor UE14.

[0108] In another example, the mobile device UE 10 may provide instructions to the anchor UE 14 to adjust its synchronization schedule, as necessary, to transmit regular synchronization signals more or less frequently, based on the identified timing error.

[0109] In yet another example, the anchor UE 14 may stop the calibration procedure with the device UE 10 upon completion of the requested ranging service, or the calibration procedure of the ranging service for the device UE 10 may be automatically stopped after a configurable timeout value expires.

[0110] In another embodiment, the power consumption of the device UE 10 or the anchor UE 14 can be optimized without compromising the accuracy of ranging and location services by setting a configurable threshold for the distance between the device UE 10 and the anchor UE 14, either directly by the device UE 10 or by the RMF 36 or LMF 34, for example based on the characteristics of the device UE 10 and / or the ranging constellation 50. The configurable threshold may be used to abort the requested ranging service if the distance exceeds the threshold and instead use the location services to obtain the desired location coordinates. Optionally, the location services may be stopped again when the distance between the device UE 10 and the anchor UE 14 falls below the threshold and the device UE 10 may use the ranging services to obtain the desired location coordinates.

[0111] In another embodiment, the power consumption of the device UE 10 or anchor UE 14 may be optimized by synchronizing the transmission and reception of signals between the device UE and the anchor UEs involved in the ranging procedure. This may be done, for example, by one of the anchor UEs or the management entity determining a schedule for transmitting the ranging reference signals, so that, for example, each anchor UE transmits the ranging reference signal to the target device UE one after the other within a short time period (e.g., burst ranging reference signal), i.e., within a short time period. The order in which each anchor UE transmits the ranging reference signal to the target UE may be pre-configured for each anchor UE by the management entity. This may be done, for example, by setting a time offset (e.g., after the start of a ranging session, or, for example, within a series of time intervals and / or within a series of pre-scheduled resources used for transmitting the ranging reference signal) for each anchor UE. Alternatively, it may be done, for example, by setting an ordered list of IDs of anchor UEs that the anchor UE may use to determine whether it is the next anchor UE in the list to transmit a ranging reference signal after receiving a ranging reference signal from an anchor UE in the list.

[0112] <<END OF SPECIFIC FEATURES FOR CALIBRATION OF RANGING CONSTELLARS (SPECIFIC TO THIS APPLICATION)>> Additionally or alternatively, the network publishing function 38 may be used (e.g., by an external application) to control network level parameters and other parameters / configuration settings required for optimal performance of ranging and location services for the mobile device of interest. These parameters may be combined with configuration parameters received from the involved devices UE 10 and / or anchor UE 14 and / or (other) management entities. In case of overlapping configuration parameters with different values, a priority scheme may be applied in which configuration parameters received from the devices UE 10 and / or anchor UE 14 and / or (other) management entities are prioritized over configuration parameters received via the network publishing function or vice versa. When overlapping configuration parameters with different values ​​are detected, the location management function 34 and / or ranging management function 36 and / or other location / ranging services or proxies thereof may discard measurements and / or measurement results and / or calculated distances / angles and / or send error messages and / or send messages to update the configuration parameters to each involved device UE 10 and / or anchor UE 14.

[0113] Similarly, if the device UE 10 and / or anchor UE 14 receives a configuration parameter or a parameter value desired to be used that conflicts with a configuration parameter (e.g., a range of valid values, or a maximum / minimum value) received from a higher priority management entity, the device UE 10 and / or anchor UE 14 may discard the ranging request, discard the measurement / measurement result, discard the calculated distance / angle, generate an error message, request an update of the configuration parameter, or request an exception from the higher priority management entity. In case of multiple management entities, the core network may set priority rules for different management entities in the policy. Conflict resolution may be done on a first-come-first-served basis, or the configuration received from the closest anchor UE may be used, for example.

[0114] Distance-based positioning In the following, a specific embodiment of ranging-based positioning will be described in further detail with reference to the network architecture of FIG.

[0115] In one embodiment, ranging or positioning between device UE 10 and anchor UE 14 may be performed according to configured parameters of a management entity in the anchor UE 14 or which may provide the configured parameters via the anchor UE 14. To this end, the anchor UE 14 or the management entity may expose to one or more device UEs 10 and / or one or more other anchor UEs 14 one or more of the configured parameters and / or values ​​(e.g., ranging method used, bandwidth / frequency used, number of antennas used) selected and / or determined by the anchor UE or management entity as parameters to be used for performing ranging procedures for ranging or location based services. This disclosure may be performed, for example, via a ProSe discovery message and / or by sending configured parameters after establishing a sidelink / PC5 connection with said one or more device UEs 10 and / or one or more other anchor UEs (e.g. via a PC5 signaling message or an RRC message or a direct communication request / accept message or via an LPP / NRPPa protocol message (which may be new messages or existing messages with additional / different fields for ranging)). In another embodiment, the ranging or positioning service may be performed by the radio access device 20 via the anchor UE 14 or by the core network 30 (e.g. a network controller device) or by a proxy. The device UE 10 and / or anchor UE 14 involved in ranging / positioning may send the configuration parameters selected and / or used to perform the ranging (e.g. ranging method used, bandwidth / frequency used, number of antennas used) (in addition to or separate from the distance / angle measurements) to a ranging service (or its proxy) or a location service (or its proxy) or a management entity (which may collect information from multiple involved UEs and send it to the ranging service or location service).The ranging or location based service may use this information to determine how to calculate position / distance / angle estimates and / or to determine accuracy estimates for the measurements, thresholds for accepting measurements, measurement / calculation error corrections, and / or to determine configuration changes for one or more of the UEs involved.

[0116] In one embodiment, to initiate ranging, the device UE 10 may send a signal to the anchor UE 14, or the anchor UE 14 may send a signal to the device UE 10, or in case of a ranging constellation consisting of more than one UE, the device UE 10 or the anchor UE 14 may send a signal to another device UE 10 and / or another anchor UE in the ranging constellation to request the initiation of a ranging session. This may be a separate signal or message, or may be indicated, for example, by setting an attribute during connection setup between the two UEs (e.g. a Boolean 'rangingrequest' attribute as part of a direct communication request message or RRCSetupRequest). This is typically done during or after the discovery phase where configured parameters (as described above) and / or possibly other characteristics of the ranging or location based services offered by the other device are identified (e.g. supported ranging capabilities, whether to act as anchor UE or not, the (preferred) ranging method to use, location information, device identifier, ranging constellation identification / identifier, key identifier, credentials (e.g. public key), nonce, location information (e.g. geographical / GPS coordinates), (supported) signal types, frequency / band information, supported or connectable PLMNs, supported or connectable location based services or location based services capabilities, supported or connectable ranging services or ranging service capabilities, synchronization / clock / timing information, whether in or out of coverage of the access device and if in coverage, the access device and access device characteristics, whether ProSe relay or other ProSe, V2X, sidelink / D2D services are supported, antenna information / configuration). Note that the above parameters may be sent during the (pre-)configuration phase or after detection (e.g. after the PC5 / sidelink connection has been set up) (e.g. via PC5 signaling or RRC messages).Also, if a request to initiate a ranging session is received by one of multiple anchor UEs in the ranging constellation, the anchor UE receiving the request may forward or issue a request to other anchor UEs in the ranging constellation, or may forward or issue a request to a ranging service or a location based service (which may then forward or issue a request to other anchor UEs in the ranging constellation).

[0117] After or upon receiving a signal to initiate a ranging session, the involved UEs may verify if the request is from an authorized UE. To that end, the UEs may have to exchange credentials and may perform authentication and / or authorization standalone or with the support of the core network (e.g., they may connect to the core network to authenticate the involved UEs and verify authorization). Upon successful authentication, one or more UEs may start transmitting ranging reference signals (e.g., position reference signals / sounding reference signals, or other signals (e.g., ProSe detection messages)), possibly using radio spectrum resources for sidelink communication or sidelink detection. This may be a signal that is repeated a set number of times (e.g., with a certain pause / quiet interval between signals) or may be a signal that is repeated until a signal to stop the ranging session is received. The (required) timing of these signals (e.g., start time of the first signal) may depend on or be determined by configured timing / delays, transmission and reception of synchronization signals, detection of stationary periods, QoS or quality of experience (QoE) information (e.g., for ranging / location services or other traffic), scheduled resources (e.g., semi-persistent resources), DRX / sleep information that may be configured and / or exchanged between devices, timing randomization functions, signal quality measurements, Doppler shift / coherence time / hysteresis of measured signals, device speed, etc. The device UE and / or anchor UE 14 may perform ranging measurements on received ranging reference signals (e.g., determine the time of arrival of the ranging reference signal, measure the angle of arrival of the ranging reference signal) and calculate the distance or angle based on the techniques described above or in other embodiments.

[0118] In another embodiment, the signal to initiate the ranging session may be sent by the access device or core network function (e.g., the Location Information Management Function 34 and / or the Ranging Management Function 36) to one or more of the involved UEs. In one example, the access device and / or core network function may know that two UEs are nearby (e.g., because both are connected to the access device), and thus the access device or core network function may instruct the two UEs to initiate a ranging session without the UEs having to perform a detection phase. The access device or core network function may provide the necessary configuration parameters so that each UE knows exactly how to perform the ranging session (e.g., frequency band or bandwidth to use, mechanism, type of signal, (temporary) device or ranging / session identifier and / or credentials to use during ranging, etc.), and may further indicate the exact timing and order in which each UE transmits signals.

[0119] It should be noted that any embodiment describing a device UE10 detecting an anchor device UE14 and / or performing a ranging session with the anchor device UE14 can be equivalently replaced with two devices UE10 detecting each other and / or performing a ranging session with each other.

[0120] Anchor UE self-configuration In one embodiment, which may be combined with other embodiments or implemented independently, the device UE 10 may configure itself as an anchor UE if it detects that there is no anchor UE 14 in the vicinity and / or if it is authorized by a management entity to operate as an anchor UE (e.g., based on a set of preconfigured policies) and / or if it has good location-based service coverage at its current location (e.g., if it detects multiple access devices with good signal strength in the vicinity that can transmit location reference signals, if it has a stable connection to a location-based service (e.g., LMF) operated by the core network through one or more access devices), and / or if it has additional means of obtaining location coordinates (e.g., via an internal GPS module). Upon self-configuration as an anchor UE, the device UE 10 may start advertising a ranging constellation and / or transmit a ranging reference signal. Before self-configuration as an anchor UE, the device UE may request and / or receive authorization to become an anchor UE from a lead anchor UE and / or a management entity and / or request / receive configuration information related to the anchor UE. A UE's self-configuration to become an anchor UE may be initiated when another device UE 10 (or anchor UE 14) initiates detection of the UE or initiates a ranging session / procedure with the UE, or when the UE initiates detection of the other device UE 10 (or anchor UE 14) or initiates a ranging session / procedure with the other device UE 10 (or anchor UE 14). If the UE meets criteria defined by a set of pre-configured policies, the UE may indicate its role as an anchor UE, or its desire to become an anchor UE, to the other device UE 10 (or anchor UE 14) when performing detection or establishing a ranging session.

[0121] In one example, based on, for example, a set of policies, the UE may decide to become itself an anchor UE 14 and report this to a management entity. To enable this, the UE may have policies / criteria (possibly with priorities) that enable it to determine whether it can become an anchor UE 14 (e.g., set an attribute in a discovery, connection setup, or ranging session setup message to a value that indicates it is / is enabled to be an anchor UE). Such policies / criteria may include whether the UE can determine its location (e.g., via GNSS), and / or whether the UE's location is stable (e.g., has a certain tolerable deviation threshold and / or fluctuates within a sufficiently small (geographical) area), and / or whether the UE is moving at a fixed speed or at a speed that fluctuates between a minimum and a maximum deviation threshold, and / or whether the signal quality / strength of the positioning / ranging signal or the signal from the access device measured by the UE exceeds a certain minimum threshold, and / or whether the measured Doppler shift / hysteresis (possibly signal strength) of the positioning / ranging signal or the signal from the access device measured by the UE exceeds a certain minimum threshold, and / or whether the measured Doppler shift / hysteresis (possibly signal strength) of the positioning / ranging signal or the signal from the access device (possibly signal strength) of the UE is / are not within a certain range, and / or whether the measured Doppler shift / hysteresis (possibly signal strength) of the positioning / ranging signal or the signal from the access device (possibly signal strength) of the UE is ... In addition to the quality threshold, the UE may include whether the UE is within the coverage of a base station, whether the UE is connected with a location / ranging service, whether the UE supports an accurate clock, whether the UE is synchronized with a particular reference clock, whether the UE supports a ranging mechanism (e.g., TDOA, round trip time), whether the UE supports sensors (e.g., barometric pressure sensor, gyroscope), and / or based on the number of antennas the UE is equipped with / supported. After the UE has determined that it can act as an anchor UE 14, it may report this to a management entity or report its desire to act as or become an anchor UE to another device UE 10 (or anchor UE 14) when performing detection or establishing a ranging session / procedure or during a ranging session / procedure.It should be noted that the determination of whether the anchor UE's position is stable may be made with reference to other UEs, e.g., UEs that are part of the constellation (e.g., device UE 10 or anchor UE 14). For example, if other UEs are moving in the same direction (e.g., UEs in the same vehicle), the absolute speed of the ranging UE 14 is not as important as the relative speed. For this purpose, the UE may receive speed and direction information from one or more nearby device UEs 10 or anchor UE 14, or may receive such information from a location service. The UE may compare the received speed and direction information and determine whether the UE can become an anchor UE 14 based on a (preconfigured) policy (e.g., a policy indicating a maximum relative speed difference or a maximum direction difference). Additionally or alternatively, the UE may report its own speed and / or direction information and / or position to a location service or a management entity (e.g., another UE). Based on the speed and / or direction information of other UEs, the location information service or management entity may determine whether the UE is moving within a maximum relative speed difference or maximum direction difference with a number of other UEs, and if so, may report to the UE that the UE can be an anchor UE and / or configure the UE to be such. Upon determining that it can be an anchor UE or after the UE has become an anchor UE, it may be notified to the management entity, and based on this, the UE may be added to the ranging constellation as an anchor UE. The management entity may update other UEs in the ranging constellation about the newly added anchor UE (e.g., by sending a new configuration).

[0122] In other words, a device and method are provided in which the device UE 10 is configured to support ranging, and the device UE 10 is further configured to receive (e.g., from a management entity) a set of policies / criteria for determining whether the device UE 10 can operate as an anchor UE, perform a set of measurements on the received RF signals, based on which the device UE 10 can determine or retrieve its location, and based on which can determine whether its location is sufficiently stable according to the set of policies / criteria, and based on which can determine whether it is within the coverage of an access device, and based on this determination, start functioning as an anchor UE 14 and / or initiate a procedure to request to become an anchor UE 14 and / or be configured as an anchor UE 14. In further embodiments, which may be combined with any other embodiment or implemented independently, the device UE 10 may stop operating as an anchor UE if it detects the presence of multiple anchor UEs 14 in its vicinity (e.g., it performs ranging device detection via a sidelink and the detection message indicates the presence of an anchor UE, e.g., via a field indicating the type of ranging device or a field indicating a ranging constellation identifier), and / or if it measures good coverage of location-based services at its current location (e.g., it detects multiple access devices with good signal strength in the vicinity that may transmit location reference signals or has a stable connection to a location-based service (e.g., LMF) operated by the core network via one or more access devices), and / or if it has additional means of obtaining location coordinates (e.g., via an integrated GPS module).

[0123] In one example, the UE may be configured (e.g., through a set of policies received from a management entity) to stop operating as an anchor UE 14 if it detects the presence of multiple anchor UEs 14 in its vicinity, and / or if it measures good coverage of location-based services at its current location, and / or if it determines that at least some number of criteria (e.g., one or more of the above criteria on which the decision to operate as an anchor UE was based) are no longer met. Once it is determined that the UE can stop operating as an anchor UE, or after the UE has stopped operating as an anchor UE, it may be notified to the management entity, and based thereon, the UE may be removed from the ranging constellation. The management entity may update other UEs in the ranging constellation about the removed anchor UE (e.g., by sending a new configuration).

[0124] In other words, devices and methods are provided that are configured for the anchor UE 14 to detect the presence of multiple anchor UEs 14 in its vicinity and / or determine its location by connecting to a location service and / or through other means (e.g., through an internal GPS module) and, based on the detection of multiple anchor UEs or the determination of its location, to cease functioning as an anchor UE 14 and / or to initiate a procedure to request ceasing to be an anchor UE 14.

[0125] In further embodiments that can be combined with other embodiments or implemented independently, a UE (e.g., device UE 10 or anchor UE 14) in a ranging constellation may be configured (e.g., by a management entity) with a policy that determines the conditions / criteria / thresholds for leaving the constellation, such as when the measured distance between the UE and one or more other UEs in the constellation exceeds a maximum distance, or when the measured distance between the UE and one or more UEs in another constellation falls below a minimum distance, or when the UE detects (via sidelink) a minimum number of UEs of another constellation, or when the measured signal strength / quality (e.g., on the sidelink or on the Uu interface) falls below a certain minimum signal strength / quality threshold, or when the number of detectable devices (via sidelink) falls below a minimum number, or when the battery falls below a certain level, etc. Upon determining that it meets one or more of the above criteria / thresholds configured by the policy, the UE may either notify the management entity to leave the constellation (the UE may indicate the constellation identifier in the notification message), or request the management entity to leave the constellation (the UE may indicate the constellation identifier in the request and / or include information about the UE's current state (e.g., its current location, its current distance from one or more UEs in the constellation, the number of detected devices (possibly including their identities), which thresholds have been exceeded, etc.), or request to join another constellation (the UE may indicate in the request a set of detected constellation identifiers or identifiers of UEs detected via the sidelink), or notify other UEs in its current ranging constellation via the sidelink to leave the constellation.In response to the request to leave the constellation or to join another constellation, the management entity may send a message that may include approval or disapproval of the UE leaving the constellation or the UE joining another constellation, and / or may configure the UE accordingly and / or update other UEs in the ranging constellation with respect to the removed UE (e.g., by sending a new configuration).

[0126] In other words, a device and method are provided in which a device UE10 or an anchor UE of a ranging constellation is configured to receive (e.g., from a management entity) a set of policies for determining conditions / criteria / thresholds for leaving the constellation, perform a set of ranging measurements with one or more UEs of the ranging constellation or one or more UEs of another ranging constellation, and / or perform detection of ranging capable devices (via sidelink), and / or perform measurements on one or more RF signals received via the sidelink or Uu interface, determine whether the measured distance is below or above a certain threshold and / or the number of detected UEs is above or below a certain minimum value, and based on this determination, leave the ranging constellation or join another ranging constellation.

[0127] Prior to self-configuration, the anchor UE may inform and receive approval from the lead anchor UE and / or the management entity. The anchor UE may make a decision to cease operating as an anchor UE based on policies set for the anchor UE by the lead anchor UE or the management entity.

[0128] In a further embodiment related to automatically configuring a UE as an anchor UE 14, which may be combined with other embodiments or implemented independently, the device UE 10 determines whether only a small number of positioning reference signals are detected from the network access device 20 (e.g., gNB) or other anchor UE 14, or the RSRP of the reference signals is below a predefined threshold at the location of the device UE 10. If so, the device UE 10 may decide to configure itself as an anchor UE 14 and start transmitting positioning / ranging reference signals. It should be noted that the device UE 10 may be configured with a capability by a management entity that allows it to configure itself as an anchor UE 14. This decision may be made based on a policy deployed by the management entity.

[0129] In other words, a device and method are provided in which the device UE 10 is configured to support ranging, and the device UE 10 is further configured to receive (e.g., from a management entity) a set of policies / criteria for determining whether the device UE 10 can operate as an anchor UE, perform a set of measurements on the received RF signals, and based on this, the device UE 10 can determine or retrieve its own location, and based on this, determine whether the number of positioning reference signals from the network access device 20 or other anchor UE 14, or the RSRP of such reference signals, is below a predetermined threshold based on the set of policies / criteria, and based on this, determine whether it is within the coverage of the access device, and based on this determination, start functioning as an anchor UE 14 and / or initiate a procedure to request to become an anchor UE 14 and / or be configured as an anchor UE 14.

[0130] Switching to a local geolocation / ranging service proxy In another embodiment, which may be combined with other embodiments or implemented independently, device UE 10 may determine (when and how) to obtain its own location coordinates from a location based or ranging service based on the ranging measurements, and one or more UEs in the ranging constellation 50 may act as a proxy for the location based and / or ranging service, for example in a particular geographic area, by supporting (a subset of) similar protocols (e.g., LPP or NRPPa) and functions (e.g., determining distance / angle / location based on position / ranging measurements, providing location / coordinates in a reference coordinate system based on a set of distance and / or angle and / or other related location information) provided by the location based or ranging service. If the device UE 10 detects that the ranging constellation 50 of a ranging-capable anchor UE 14 is providing location coordinates, operating location / ranging services, and / or acting as a proxy for location / ranging services in the vicinity, and / or if the device UE 10 determines that the signal coverage of the access devices is insufficient in a particular geographic area (which prevents its proper / efficient use of location services), and / or if it enters a particular tracking area or is close to a particular access device, and / or if it meets a set of conditions defined by a pre-configured policy (e.g., if it can detect a certain minimum number of anchor UEs), the device UE 10 may automatically turn off the use of location services provided by the core network / access device (e.g., terminate the connection to the LMF 34). Additionally / or, the device UE 10 may turn off the use of location services provided by the core network / access device when it receives an explicit signal from the location / ranging service or management entity.

[0131] In further embodiments, which may be combined with other embodiments or implemented independently, the device UE 10 may self-configure or be configured by a management entity to use ranging services within a particular geographic area (e.g., within a building) and location services outside that particular geographic area (e.g., outside the building). The ranging measurements may be transmitted to the RMF 36 and / or the LMF 34 and / or another location / ranging service, or a proxy thereof, which may convert the ranging measurements into geographic or relative location coordinates. The measurements may be transmitted by the device UE 10 and / or the anchor UE 14 of a particular ranging constellation 50 and / or the head anchor UE of the ranging constellation 50. The ranging measurements between the device UE 10 and multiple nearby anchor UEs 14 may be transmitted separately or may be consolidated into a single report that is forwarded to the RMF 36 and / or the LMF 34 or another location and / or ranging service, or a proxy thereof. For this purpose, participating UEs may transmit measurements and / or estimated distances / angles between themselves and one or more other UEs of the ranging constellation to the head anchor UE. If one or more anchor UEs are out of coverage, another (head) anchor UE that is in coverage may act as a proxy for RMF, LMF, or other location-based or ranging services. In this case, the in-coverage UE may transmit measurements or reports. If the entire constellation including the head anchor UE is out of coverage, the head anchor UE may act as a proxy for certain functions (e.g., a subset of functions) of RMF and / or LMF or other location-based and / or ranging services. These functions may include converting distance, time, and angle measurements to location coordinates, calibrating ranging measurements, temporarily storing measurements until the communication link with the access device is restored, etc.

[0132] Alternatively or additionally, if approved by the device user, the ranging service, location service, RMF 36 or LMF 34 may securely share the ranging measurements with an application function 40 (e.g., a third party application) via the NEF 38 to calculate the location coordinates of the device UE 10.

[0133] In embodiments related to switching to ranging services or ranging-based positioning services, the management entity may configure a ranging-assisted constellation (e.g., ranging constellation 50) together and track the locations of those in a particular geographic area where there are a sufficient number of ranging-enabled devices (e.g., with their current location set or with active location services) that can act as proxies for location services. The management entity may use this information to declare the set of ranging-enabled devices that compose the ranging constellation 50 and / or configure the necessary parameters of the devices (e.g., anchor UE 14) accordingly (as described in other embodiments). The management entity may also configure the set of devices UE 10 with information about the ranging constellation 50 (e.g., constellation identification information, number of anchor UEs, area information, frequencies / resources to use, etc.). This may include information (e.g., information in the form of policies) that associates the use of ranging services with location / geographical area information / tracking area / registration area / cell ID / synchronization signal block (SSB) index. The device UE 10 may self-configure or be configured by a management entity (e.g., based on (detected / configured) information about one or more ranging constellations in the area) to use ranging services in a particular geographic area upon entering this geographic area. For this purpose, the device UE 10 may use policy information (e.g., received from a management entity) that associates the use of ranging services with location / geographical area information / tracking area / registration area / cell ID / synchronization signal block (SSB) index. The device UE 10 may use tracking area information / cell ID / SSB information received from an access device, relay device, or detected ranging-enabled device and associate this with the policy information to determine whether to enable ranging and / or which constellation and / or anchor UE 14 to use.As an example, a management entity may advertise the presence and type of ranging or ranging-based location services in a particular geographic area by requesting wireless access devices to include ranging information in SIBs (e.g., SIB1) broadcast by wireless access devices within that geographic area. The wireless access devices broadcast the presence of ranging or ranging-based location services in that area by broadcasting such SIBs. Upon receiving the SIB, the device UE 10 may recognize the presence of the ranging services and may access the ranging-based location services or activate a sidelink to provide the ranging-based location services.

[0134] In one embodiment, the device UE 10 may be configured with a list of approved constellation identifiers and / or anchor UEs 14 that it can select and / or connect to in order to start ranging. Also, possibly, credentials may be configured to allow secure communication setup with the devices of the constellation, i.e., the anchor UEs 14. This list may be prioritized. Alternatively or additionally, the device UE 10 may be configured with policies specifying a minimum number of anchor UEs 14 present in the constellation and / or detectable in the vicinity of the device UE 10, and / or requirements on the capabilities and / or characteristics of the anchor UEs 14 (e.g., anchor UE (relative) movement below / within a certain threshold, minimum / maximum distance from the device UE 10, signal strength threshold, geographical area information, tracking area information, PLMN information). Based on these policies, it may be decided whether the device UE 10 should turn on ranging or start a ranging session, or a set of constellations / anchor UEs to select / connect to for ranging may be decided. Device UE10 may also use its own position estimated based on other means (e.g., GPS, WiFi, or trajectory interpolation with dead reckoning based on built-in accelerometers, etc.) to determine whether to use ranging services.

[0135] When the device UE 10 decides to use the ranging service, the device UE 10 may turn on the detection of other ranging-enabled UEs in the vicinity and / or connect (directly via Uu or via a relay device) to a ranging or location-based service provided by a network (e.g., provided or managed by the LMF 34 or RMF 36) that may further instruct / configure the device UE 10. Alternatively, the detection of other ranging-enabled UEs may always be on and the decision to use ranging may be made based on detection information from other ranging-enabled UEs (e.g., whether the detected UE is an anchor UE or not, or based on (detection / configuration) information regarding one or more ranging constellations in the area (e.g., based on constellation identification information detected via one of the ranging-enabled UEs), or detecting the presence of one or more UEs that constitute a ranging / positioning constellation).

[0136] The UE 10 may still use other existing positioning services.

[0137] Similarly, the anchor UE 14 may be configured by a management entity or by itself to turn on ranging / ranging services (e.g., to start sending and / or receiving detection messages and / or start a ranging session) when it enters a geographical area or when the device UE 10 enters the area. Note that every time the device UE 10 or anchor UE 14 enters a new area or comes close to a new ranging constellation, it may need to request or receive a new / fresh authentication and / or obtain a new / fresh set of credentials from the core network / access device / RMF / LMF / (head) anchor UE via Uu direct connection or PC5 direct / indirect connection before or when establishing a new ranging session or joining the new ranging constellation.

[0138] In a related embodiment, the management entity may be configured to automatically reconfigure the device UE 10 to connect to location services to obtain location coordinates when the device UE 10 leaves a particular geographic area, and the device UE 10 may reconfigure itself (e.g., based on a policy that associates the use of positioning services with location / geographic area information / tracking area / registration area / cell ID / synchronization signal block (SSB) index).

[0139] Alternatively, the management entity may automatically turn on or off ranging and location based services depending on the last known location of the device UE 10.

[0140] When device UE 10 detects a constellation of nearby ranging-enabled UEs (e.g., ranging constellation 50) that can provide location coordinates, it may automatically turn off location services (e.g., terminate the connection to LMF 34). The location coordinates may be obtained directly as a result of ranging measurements, or by converting the ranging measurements into location coordinates via a location service known to the constellation of ranging-enabled UEs.

[0141] In another / independent embodiment related to switching to ranging services or ranging-based positioning services, when the device UE 10 is temporarily disconnected from the LMF 34 or other location services provided by the core network, such as when out of coverage, it may automatically turn on ranging services to look for nearby ranging-capable anchor UEs 14 and / or constellations (e.g., ranging constellations 50). For this purpose, the device UE 10 may be configured with policies that determine conditions, such as, for example, minimum / maximum signal strength (e.g., RSRP) or other signal quality parameters (e.g., RSRQ, number of failed connection attempts) of signals received from nearby access devices, below / above which the use of ranging and / or positioning services may be turned on or off.

[0142] Detecting and requesting use of ranging constellations In an embodiment, an anchor UE providing ranging and / or location services (e.g., ranging-based positioning services or proxies thereof) may provide ProSe / V2X / D2D services to access such ranging and / or location services over a sidelink, e.g., to obtain / provide location information or initiate ranging. Such ProSe services may be signaled by sidelink discovery via a specific ProSe / V2X / D2D service identifier or application code, after which other UEs may establish a connection to such services over a sidelink and utilize the services. The LMF 34, RMF 36, or other ranging and / or location services, or other management entities may provide credentials that enable and / or can be used for protection of discovery and / or message exchanges between the ranging-enabled device UE 10 and the anchor UE 40.

[0143] In further embodiments, the device UE 10 may be configured to obtain or request its own location coordinates based on ranging measurements from one or more anchor UEs 14 of the ranging constellation 50. The anchor UE 14 may advertise a ranging reference signal (e.g., that may be detected by nearby device UEs 10 based on frequency, timing, signal characteristics / type, waveform, bandwidth, configured resources), or advertise ranging-based positioning (combination of ranging and location services capabilities) as ProSe, or advertise support for ranging / location services and / or other ranging / location capabilities, or provide information about its (last known) location, or transmit detection messages within configurable time intervals configured (e.g., by a management entity) on UEs known to ranging services and / or involved in the particular ranging constellation 50 to which the anchor UE 14 belongs. This allows the device UE 10 to identify and verify the integrity of the advertising / discovery message, determine the arrival time of the advertising / discovery message, and extract from the message, for example, timing information (e.g., the sending time of the advertising / discovery message contained therein, the processing time of the message to which this message is a response (e.g., t3-t2 for FTM), the reception interval of the message to which this message is a response, clock synchronization information) to calculate the distance between the device UE 10 and one or more anchor UEs 14 of the ranging constellation. Furthermore, the device UE 10 can calculate a bounded area that approximates its location coordinates based on one or more distances obtained, for example, from round-trip time measurements and / or time-of-flight estimates between the device UE 10 and one or more anchor UEs 14. Furthermore, the device UE 10 may receive, via the RMF 36 or LMF 34 or management entity, a list of authenticated anchor UEs 14 present in its vicinity, and upon approaching an authenticated anchor UE 14 within its ranging distance (e.g., after detecting such an authorized anchor UE), may connect to the anchor UE 14 and / or request the use of ranging / location services or a service proxy provided by such anchor UE.The device UE 10 may obtain location coordinates (e.g., calculated coordinates of the device UE 10, location coordinates of the anchor UE 14, and / or location coordinates of one or more access devices or position reference units) and / or estimated relative positions / distances / angles between one or more devices of the constellation from the anchor UE 14 without using the RMF 36 or LMF 34 or other location information services of the core network 30 (e.g., network controller devices). In this case, the anchor UE 14 may use a ranging procedure / service to measure the distance and / or angle between itself and the device UE 10 and convert the distance to a location coordinate based on the current location coordinates locally on the device. Alternatively, the device UE 10 may measure the distance and / or angle using a ranging procedure / service and forward it to the anchor UE 14 requesting that the measured distance be converted to a geographic coordinate.

[0144] In another embodiment, the anchor UE 14 may provide its geographic coordinates to the device UE 10, which the device UE 10 may use after measuring the distance and / or angle to the anchor UE 14. The transmission of the geographic coordinates of the anchor UE 14 needs to be done in a secure manner with respect to integrity and / or confidentiality. Thus, the anchor UE may provide the coordinates only after a secure communication channel is established between the device UE 10 and the anchor UE 14, and / or transmit the geographic coordinates protected by a key that allows only the device UE 10 or a set of authorized device UE 10 to decode this information and / or allows the device UE 10 or a set of authorized device UE 10 to verify the integrity of the information (by a message integrity code or a digital signature).

[0145] In one embodiment, instead of transmitting information about the location of the anchor UE 14 (e.g., geographic coordinates) to the device UE 10 or another anchor UE, the anchor UE 14 may transmit an identifier (e.g., a location identifier pre-configured / assigned to the anchor UE by a location service / database or self-assigned) to the device UE 10 or another anchor UE (e.g., in a discovery message, a connection setup message, a PC5 signaling message, or a user plane message (e.g., a message over the IP layer)), possibly together with a location service / database identifier or address. The device UE 10 or other anchor UE receiving this identifier may use it to retrieve the location coordinates of the anchor UE via a secure connection with a location service / database (e.g., identified by an optionally provided location / database identifier or address, or a default location service / database known to the UE or the core network to which the UE is connected). To enable this, the anchor UE (e.g., configured / authorized by a user or a management entity), the anchor UE on behalf of the management entity, or the management entity on behalf of the anchor UE may give permission to retrieve the location of the anchor UE by doing one of the following: - providing the device UE 10 or other anchor UEs with authentication credentials (e.g. authentication tokens) that can be used to verify / verify the authenticity of the authentication (i.e. authentication provided by the connected anchor UE 14), e.g. by performing an authentication procedure with the respective anchor UE 14 or by checking that the credentials match or are securely associated with credentials of the device UE 10, the other anchor UE, or an LMF 34, RMF 36 or other location and / or ranging service, or a proxy thereof, or other management entity, or a core network function (e.g. UDM / AUSF) to which the device UE 10 or other anchor UE can be connected; and / or - by providing an authentication message / credentials to the respective LMF 34, RMF 36 or other location and / or ranging service, their proxy or other management entity, or location database, verifying that the message / credentials originated from the respective anchor UE (e.g. performing an authentication procedure with the respective anchor UE 14) or by checking that the credentials match or are securely associated with previously stored credentials of the anchor UE 14 within the LMF 34, RMF 36 or other location and / or ranging service, their proxy or other management entity, or core network function (e.g. UDM / AUSF); and / or - By granting permission by providing consent within a subscription (e.g. UDM) or by providing consent through a Network Publishing Function (NEF).

[0146] In a further embodiment, the device UE 10 may calculate its own location coordinates based on ranging reference signals obtained from one or more anchor UEs 14 via a sidelink channel (e.g., via a sidelink detection message or other signal transmitted using sidelink resources) and location information of the one or more anchor UEs 14. For this purpose, the device UE 10 and one or more anchor UEs 14 may exchange messages to initiate a ranging session. One or more of these messages may include a ranging session ID (which may be used by all UEs involved in participating in the ranging session) and / or may include a ranging constellation identification and / or may include a ranging reference signal. The ranging reference signal may include (encoded) information regarding the type of reference signal, the UE's identification, the ranging session ID, the ranging constellation identification, the constellation's identification, the credentials, the nonce, timing information, and / or distance / angle / location information.

[0147] In further embodiments, when the device UE 10 initiates ranging with two or more anchor UEs, the device UE 10 may indicate the number of anchor UEs and / or a set of anchor UE identifiers and / or a constellation identifier as part of a message for initiating a ranging session (e.g., a direct communication request with a field indicating a request for ranging services (e.g., using an application or service identifier defined for this)). These messages may be sent as multicast / broadcast messages to all involved anchor UEs, which may initiate ranging with the device UE 10 and / or transmit configuration parameters for ranging to the device UE 10. Alternatively, these messages may be sent in a unicast message to one of the anchor UEs (e.g., the head anchor UE), which may receive this unicast message and transmit respective messages to other anchor UEs in or near the constellation inviting them to join the ranging session and / or initiate ranging with the device UE 10 and / or transmit configuration parameters for ranging to them.

[0148] In further embodiments, the location coordinates of the anchor UE 14 may be exchanged with the device UE 10 via a sidelink channel, and the location calculation may be performed after the device UE 10 achieves clock time synchronization (simultaneously) with those anchor UE 14 and / or after connecting to one or more anchor UE 14. By using time difference of arrival, round trip time, and / or time of flight measurements based on ranging reference signals, the distance between the device UE 10 and one or more anchor UE 14 can be calculated and the distance can be exchanged between the device UE 10 and one or more anchor UE 14 (e.g., via a connection established between the device UE 10 and one or more anchor UE 14). Also, angles can be determined if the device UE 10 or anchor UE 14 has multiple antennas. Assuming that the device UE 10 and one or more anchor UEs 14 are in the same horizontal plane (i.e., at similar altitudes) and the distances and / or angles between the anchor UEs 14 are known or can be calculated (e.g., based on the geographic coordinates of the anchor UE 14 and / or distance / angle measurements performed between two or more anchor UEs 14 (results of the distance / angle measurements can be shared with the device UE 10 and / or a ranging / location service)), the location of the device UE 10 can be estimated based on trilateration and / or triangulation by using the distance measurements between the device UE 10 and at least two anchor UEs 14 (and information about the known or calculated distances and / or angles between the anchor UEs, and / or the position coordinates of the anchor UE 14), or the distance and angle measurements between the device UE 10 and at least one anchor UE 14 (and information about the known or calculated distances and / or angles between the anchor UEs, and / or the position coordinates of the anchor UE 14).

[0149] To account for possible altitude differences between UEs in a ranging constellation, the device UE 10 may need to make distance and / or angle measurements with additional anchor UEs as additional references.

[0150] Using Non-RF Sensors According to an embodiment, which may be combined with other embodiments or implemented independently, the device UE 10 may be equipped with other means for determining relative altitude (i.e., difference from a known reference altitude) or absolute altitude (i.e., difference from sea level), such as a barometric pressure sensor. If the anchor UE 14 knows its own altitude (e.g., altitude relative to sea level or a particular horizontal plane), for example determined by a barometric pressure sensor or GNSS, the anchor UE 14 may transmit information about its altitude (e.g., as a Z-axis coordinate (e.g., a 3D coordinate or Z-axis value), as an altitude in meters from sea level or a particular reference horizontal plane, or as a barometric pressure value) to the device UE 10. The device UE 10 may use this information to calculate the altitude difference between the device UE 10 and the respective anchor UE 14. Alternatively, the device UE 10 may share information about its altitude with the anchor UE 14 and / or the ranging / location service to calculate the altitude difference. The calculated / estimated altitude difference value may be used in a subsequent (3D) position coordinate calculation to estimate the location of the device UE 10, including altitude, taking into account the determined altitude difference between the device UE and one or more anchor UEs 14. Similarly, the position calculation may include using other sensing information collected by the target mobile device (or anchor device), such as a magnetic sensor (e.g., magnetometer) that provides information regarding the angle of the target mobile device (e.g., UAV), or a sonar sensor that provides information regarding the altitude of the target UE (e.g., UAV) relative to the ground, or a non-RF sensor that provides an additional means for measuring distance (e.g., using ultrasound).In other words, an apparatus (e.g., anchor UE 14 providing ranging / location services, or RMF 36 or LMF 34) for calculating the position of a target mobile device (e.g., device 10) may be adapted to calculate position coordinates of the target mobile device based on ranging reference signals obtained from one or more anchor devices of a ranging constellation via sidelink channels and sensing information collected by the target mobile device or anchor UE and provided as input to the apparatus for calculating the position of the target mobile device. Additionally, or independently, if device UE 10 or anchor UE comprises means for determining x-axis or y-axis coordinate values ​​(e.g., coordinate values ​​relative to a preconfigured reference plane and / or coordinate system), such values ​​may be transmitted to the apparatus and the position of the target mobile device may be calculated.

[0151] In an embodiment, device UE 10 requiring ranging over sidelink / PC5 and supporting anchor UE 14 may be configured to perform ranging by non-RF sensors (e.g., ultrasonic sensors) and / or exchange capabilities / configurations related to ranging capabilities enabled by non-RF ranging sensors (e.g., ultrasonic sensors). In particular, device UE 10 or anchor UE 14 may operate as an ultrasonic source, e.g., using a speaker, or as an ultrasonic receiver, e.g., using a microphone.

[0152] In one embodiment related to this embodiment, device UE 10 requiring ranging over the sidelink / PC5 interface and anchor UE 14 supporting ranging may rely on "non-sidelink ranging reference signals" that are not exchanged over the sidelink / PC5 interface but whose parameters of the signal are configured or announced over the sidelink / PC5 interface. In particular, "non-sidelink ranging reference signals" may refer to ultrasound signals generated by, for example, device UE 10 or anchor UE 14 and received by anchor UE 14 or device UE 10, respectively. In particular, the parameters of the ultrasound signal may include the frequency of the ultrasound signal (e.g., 40 KHz), the timing (start time) of the ultrasound signal, or an identifier (e.g., modulation of the ultrasound signal).

[0153] In a related embodiment, the device UE 10 acts as an announcing UE and may transmit (e.g., sporadically or periodically) detection messages that are received by the anchor UE 14 acting as a monitoring UE. The detection messages transmitted by the device UE 10 may include a timing or an identifier of the "non-sidelink ranging reference signal", e.g., a given delay for the transmitted detection message. The detection message may also include the temperature / humidity measured by the device UE 10, since these are factors that affect the speed of sound in air. At least one anchor UE 14 (monitoring) in the ranging constellation 50 may receive the detection messages, know the parameters of the "non-sidelink ranging reference signal", and then measure the "non-sidelink ranging reference signal" to obtain ranging measurements with the device UE 10.

[0154] The use of such a "non-sidelink ranging reference signal", e.g. an ultrasonic signal, has several advantages, such as allowing accurate ranging measurements due to the low speed of sound in air compared to the very fast propagation of messages over the sidelink / PC5. For example, in the above embodiment, assuming that the device UE 10 and the anchor UE 14 are 10 m away from each other, there is a delay of 1 / 3+10^(-7) seconds in sending the detection message. Assuming a clock synchronization error of 1 / 3*10^(-6) and that both the device UE 10 and the anchor UE 14 use a speed of sound of 340 m / s for an actual speed of 339 m / s, the ranging result is 9.97 m.

[0155] Licensed / Unlicensed Spectra In one embodiment, which may be combined with other embodiments or implemented independently, the device UE 10 or anchor UE 14 may have a policy for determining whether licensed or unlicensed spectrum can or should be used for a particular location / geographical area information / tracking area / registration area / cell ID / synchronization signal block (SSB) index (and may also include information about preferred frequencies / bands, bandwidth, etc.). One additional criterion for determining whether licensed or unlicensed spectrum can or should be used, which may be part of the policy information, is whether the device UE 10 and / or anchor UE 14 is in or out of coverage of the access device. If both UEs are in coverage, then typically licensed and unlicensed spectrum is allowed to be used, and if both UEs are out of coverage, then typically only licensed spectrum is allowed to be used since the mobile network operator would want to control the use of licensed spectrum. A specific situation is when one UE involved in the ranging session (e.g., device UE 10) is out of coverage and another UE involved in the ranging session (e.g., anchor UE 14) is in coverage. This situation may change because the UEs may also move. Therefore, it is important that the UEs involved in ranging can inform each other in advance (e.g., via core network functions) and / or during detection, connection setup, initiation of the ranging session, and / or during the ranging procedure of their coverage status. The UEs can determine whether they are out of coverage or not based on some (pre-configured) threshold on signal quality / signal strength. If the signal quality / strength is below a certain threshold, the UE is considered to be out of coverage.The UE (UE1) may expose its coverage status (e.g., in-coverage or not) as a field in a transmitted detection message or synchronization signal such as a sidelink synchronization signal (e.g., using a Boolean value indicating whether it is in network coverage or not, or by exposing a signal quality / strength value / level (e.g., associated with a set of access devices 20) measured by UE1, or by exposing cell ID information received from nearby access devices 20), or by transmitting a detection response message or synchronization signal in a different (e.g., unlicensed) frequency band than the detection request message or synchronization signal transmitted by another UE (UE2). If the receiving UE (UE2) receives a detection message or synchronization signal indicating that the other UE (UE1) is out of coverage, it may be configured / requested / instructed to use unlicensed radio spectrum resources instead of licensed resources to establish a subsequent connection to initiate a ranging session or to perform ranging using a ranging reference signal. A UE receiving a detection message or synchronization signal may be pre-configured (e.g., by a policy) to be able to connect to licensed resources instead as an exception if the UE receiving the detection message or synchronization signal is itself within the coverage of the network. Such pre-configuration / policy may further define distance or area information indicating a maximum allowable displacement between the UE receiving the detection message or synchronization signal and the UE transmitting the detection message or synchronization signal, within which the use of licensed spectrum is permitted, and outside which the use of unlicensed spectrum is restricted. A UE receiving a detection message or synchronization signal may be configured / requested to limit the transmission power of subsequent signals transmitted in the licensed spectrum to prevent the signals from propagating beyond the maximum allowable distance. If the receiving UE can locate itself within the pre-configured area information, it may be configured / requested to limit the transmission power of subsequent signals transmitted in the licensed spectrum to prevent the signals from propagating beyond the allowable area.Similarly, during subsequent message exchanges for connection setup, initiation of a ranging session, or performing ranging using a ranging reference signal, each UE can transmit information about its coverage status using an attribute in one of those messages or as a separate message (e.g., a MAC Control Element that can be concatenated in one of those messages). If a change in coverage status occurs during these procedures, the involved UEs need to switch the frequency / band used. For example, if these UEs were initially communicating in a licensed band, the UEs may be configured / requested / instructed to switch to an unlicensed band. For this purpose, at least one UE may need to perform a configuration change procedure to inform the other UEs to switch to another band and continue the procedure by indicating the new frequency and / or updated coverage status in a message sent to the other UEs. Instead of a message exchange to determine the new frequency to be used, a default / fallback frequency may be configured in the involved UEs to continue the procedure if one UE receives a coverage status update of the other UE. Alternatively, a time interval may be configured for the involved UEs that is exempt from switching frequency bands, for example for a few seconds or until the ranging procedure is finished (e.g., part of a constant burst of the ranging reference signal). Also, a maximum distance at which the licensed spectrum is allowed to continue and at which the unlicensed spectrum must be used may be configured for the UEs. Using the ranging results obtained so far, the UE may determine that the distance is within the limits to continue using the licensed spectrum or is outside the limits and therefore needs to switch to the unlicensed spectrum. In a related example, the device UE 10 is out of coverage and the anchor UE 14 is in coverage, and the anchor UE 14 may know its location or provide a location / ranging service proxy or have access to the location / ranging service.The device UE 10 may perform ranging in the unlicensed spectrum to determine the distance and / or angle between itself and the anchor UE (using one of the methods described above) and / or may receive a signal (e.g., a detection message or other ranging reference signal) from the anchor UE 14 (which may transmit such a signal from time to time on a pre-configured set of licensed / unlicensed radio spectrum resources) to cause the device UE to determine the distance and / or angle (using one of the methods described above). Using the measured distance and / or angle, the device UE 10 may determine a location estimate (either on its own after receiving information about the anchor UE's location, or by using a location / ranging service proxy, or by accessing a location / ranging service (e.g., via a relay connection and / or by using the last known location of the device UE 10 or the anchor UE 14)) and based on this location estimate, may determine that it is located within a particular geographical area where it is configured / authorized to use licensed spectrum (for a particular PLMN) to use sidelink resources (e.g., for communication / ranging purposes). In a related example, a first device (FD) that is out of coverage and a second device (SD) that is out of coverage are assumed. In this case, the FD may transmit a sidelink synchronization signal (SSS) in the unlicensed spectrum to listen for SSS in both licensed and unlicensed spectrum. The SD may receive the FD's SSS (indicating out of coverage) and announce its presence to the SD. The SD may do this using the unlicensed spectrum and perform ranging in this spectrum, or the SD receiving these SSS from the FD may notify the FD and, based on policy, decide to transmit SSS in the licensed spectrum so that the FD can establish connections and use ranging in the licensed spectrum.

[0156] speed estimation In one embodiment, upon detecting a ranging capable device within the ranging distance, the device UE 10 may measure the distance and angle with the ranging capable device (e.g., anchor UE 14) and continuously track these measurements and timing for each distance the device UE has moved relative to the first measurement made by the device UE 10 and the detected ranging capable device. While tracking the distance and angle measurements obtained from the ranging capable device along the moving trajectory, the device UE 10 may periodically attempt to reacquire a connection to the LMF 34, RMF 36, or other location based service provided by the core network or anchor UE, or may attempt to obtain new location coordinates from the ranging capable device. This allows the device UE 10 to estimate its relative speed and / or moving pattern / trajectory. If information regarding the absolute / geographical position and / or speed and / or moving pattern / trajectory of each anchor UE 14 and / or information regarding whether each anchor UE 14 is stationary or not is forwarded to the device UE 10 (or vice versa), the absolute speed and / or moving pattern / trajectory of the device UE 10 in the fixed / absolute / geographical coordinate system may also be calculated.

[0157] In one example, inertial sensors (eg, accelerometers and / or gyroscopes, etc.) possessed by device UE 10 may be used to assist the ranging service in identifying and tracking a movement trajectory.

[0158] Data from such inertial sensors may be processed locally on the device UE 10 to calculate the distance and direction that the device UE 10 has moved since the moment that the device UE 10 lost connection to the location and / or ranging service. The device UE 10 may locally calculate a movement trajectory based on the distance and direction moved and combine this information with the most recent known location coordinates to determine the current coordinates of the device UE 10. Alternatively, the device UE 10 may attach the distance and direction information calculated based on the inertial sensors to a detection message or other message (e.g., a direct communication request message or a PC5-RRC message) sent over the PC5 interface. The anchor UE 14 receiving such a message (and also capable of performing ranging and / or location services) or the RMF 36 and / or LMF 34 (to which the distance / direction information based on the inertial sensors may be forwarded) may calculate the current coordinates based on the inertial sensor measurements from the device UE 10. Depending on other factors such as the error rate of ranging measurements in a particular environment and user settings and / or device capabilities, distance and direction calculated from inertial sensor measurements may optionally be used or may be used in addition to the ranging measurements.

[0159] Upon re-establishing a connection with the LMF 34 or other location-based service provided by the core network or anchor UE and obtaining current location coordinates, the device UE 10 may automatically recalculate its location coordinates based on its most recent known location coordinates and the distance and angle measurements obtained while the connection to the LMF or other location-based service was broken. Alternatively, upon re-establishing a connection with the LMF 34 or other location-based service provided by the core network or anchor UE, the device UE 10 may transmit (e.g., to a nearby anchor UE 14 or other ranging-enabled UE) the distance and angle measurements obtained while the connection to the LMF 34 or other location-based service was broken, as well as its most recent known location coordinates. This allows the LMF 34 or other location-based service to quickly determine the current location of the device UE 10.

[0160] It should be noted that while performing a ranging operation with the device UE 10, the anchor UE 14 in the ranging constellation 50 may report the identity / ranging measurements of the device UE 10 to a ranging service or location service, or other location / ranging service provided by the LMF 34, RMF 36, or core network, or a proxy provided by the anchor UE 14, so that the location coordinates corresponding to the current location of the device UE 10 can be updated in the location registry.

[0161] Use of FR1 / FR2 to assess prospects In another embodiment, which may be combined with other embodiments or implemented independently, the device UE 10 and the anchor UE may transmit and / or exchange positioning signals and / or messages in different frequency bands (e.g., FR1 and FR2 frequency bands). Possibly, this may be performed using carrier aggregation (i.e., simultaneous transmission in two bands of a ranging reference signal that may be duplicated or split between two different bands) or by using different bands intermittently. The term "positioning signal" as used herein and in subsequent embodiments may be used in the context of location-based services using an access device (e.g., access device 20 using an infrastructure connection / Uu interface) and may also be used with respect to ranging signals for determining the distance and / or angle between two devices (e.g., using a sidelink / PC5 interface).

[0162] For example, in a first step, the device UE 10 may receive or transmit a message requesting / offering ranging services in the FR1 frequency band. In a second step, the device UE 10 may receive or transmit a positioning signal in both the FR1 and FR2 frequency bands. The device UE 10 may use the signal quality or distance measurement results of the message (e.g., ranging reference signal) transmitted in the FR1 frequency band to determine whether the device UE 10 is located sufficiently close to and / or within line of sight (LoS) with another ranging-enabled UE and to determine whether to transmit a signal in FR2. This decision may be based on device capabilities or indications received from the other ranging-enabled device, which allows the device to determine that the other ranging-enabled UE supports FR2. For this purpose, for example, during discovery or connection setup between two ranging-enabled UEs, the capable and / or preferred frequencies / bands of the ranging-enabled UEs may be published / exchanged. Similarly, carrier aggregation capability and / or capable bands for carrier aggregation may be published / exchanged. In a third step, the device UE10 or anchor UE14 may collect measurements of their positioning signals and, optionally, transmit them to a management entity or ranging / location service for evaluation. In a fourth step, the device UE10 or anchor UE14 or management entity or ranging / location service may determine LoS characteristics of the communication link based on the collected measurements. The positioning signals or messages may aid, for example, in the calculation of round trip times. If the measurements are performed when exchanging positioning signals or messages in the FR1 band, the measurements are likely to be successful even in the absence of direct LoS (e.g., even if the devices are separated by walls in a house). On the other hand, if the measurements are performed when exchanging positioning signals or messages in the FR2 band, the measurements are less reliable due to poor propagation of wireless messages in the FR2 band. Note that not all steps are always necessary, and the steps may be performed in a different order.

[0163] Thus, based on these measurement results (especially if the measurements in FR1 are successful and the measurements in FR2 are not successful), it can be determined whether the device UE 10 and the anchor UE 14 are in line of sight with each other. Based on whether the device UE 10 and the anchor UE 14 are in line of sight with each other, the UE can decide to use only FR1 frequencies (or lower frequencies) for ranging or communication, select a specific subset of FR1 frequencies for ranging or communication, change the ranging method used, decide to stop / start ranging, or decide whether to set up a connection and / or ranging session.

[0164] Alternatively, measurements made in the FR1 and FR2 bands may be analysed, for example by a management entity, to show whether the received power changes as expected when LoS is obtained.

[0165] The transmitting UE may vary the transmit power of signals in different frequency bands such that the receiver is expected to measure similar and / or specific values ​​for signal strength / quality (according to the calibration information) and may include the transmit power information as part of the positioning signal and / or as a pre-exchanged message (e.g., as part of setting up the ranging session).

[0166] Another way to determine whether two UEs are within LoS range is to exchange positioning signals that include subcarriers at both FR1 and FR2 frequencies. The measured signal strengths of the positioning signal subcarriers at FR1 and FR2 frequencies are used to determine the LoS characteristics of the communication link. If the anchor UE and the UE are within LoS, the positioning signal transmitted at the FR2 frequency will be properly received, but if there is an obstacle (e.g., a wall) between them, the received positioning signal will be received with lower power (e.g., RSRP) or signal quality (e.g., RSRQ) compared to the received positioning signal transmitted at the lower FR1 frequency, or not received at all. For this purpose, the transmitting UE may vary the transmission power of the signals at the different subcarriers such that the receiver is expected (according to the calibration information) to measure similar values ​​for signal strength / quality, and may include the transmission power information as part of the positioning signal and / or as a pre-exchanged message (e.g., as part of the ranging session setup).

[0167] Centralized Location In an embodiment related to centralized positioning based on ranging measurements with an anchor UE node 14, the device UE 10 may approach an anchor UE 14 of a ranging constellation 50 to perform ranging measurements. Upon receiving a ranging request from the device UE 10, the anchor UE 14 may inform the device UE 10 about the ranging constellation 50 via the LMF 34, RMF 36, or other location or ranging service, or another communication channel. The device UE 10 may store the constellation information and, as long as it is in the vicinity of the ranging constellation 50, may decide whether to receive position coordinates based on ranging measurements from one or more anchor UEs 14 or other UEs that are part of the ranging constellation 50 (which may provide ranging services and / or act as proxies for location services). The device UE 10, the other device UEs 10, and the anchor UE 14 may be part of a positioning constellation 60, which allows the location service to (centrally) determine the location of the device UE 10. The device UE 10 may connect to and / or receive information from the LMF 34, RMF 36, or other location-based or ranging services provided by the network directly via the Uu interface or via a relay connection between the device UE 10, another UE, and the access device 20 providing access to the LMF 34, RMF 36, or other location-based or ranging services (e.g., via a secure connection or by being exposed via a relay device discovery message). The anchor UE 14 or ranging-enabled device UE 10 may act as such a relay device (e.g., using a ProSe relay service) for other UEs (e.g., other UEs that are part of a positioning constellation). UEs that are part of a ranging or positioning constellation may be configured with certain identification information and parameters, such as a relay service code and / or discovery credentials.The relay service code and / or discovery credentials, for example, enable other UEs that are part of the constellation and / or that are located nearby and / or that are capable of ranging and / or location services to access the LMF34, RMF36, or other location services and / or ranging services via a ProSe relay connection based on that particular relay service code. The LMF34, RMF36, or other ranging and / or location services, or other management entities, can provide credentials that enable and / or can be used for protection of discovery and / or message exchanges between the ranging enabled device UE10 acting as a remote UE, the UE acting as a relay device, and the ranging / location services.

[0168] When the device UE 10 needs to obtain its location (e.g., geographic) coordinates, it may initiate a ranging request via a ranging service with any anchor UE 14 of the ranging constellation 50, indicating that it needs location coordinates. Upon receiving the request for location coordinates, (at least) one anchor UE 14 of the ranging constellation 50 may perform ranging measurements and share its ranging measurement results with the RMF 36 and / or LMF 34, etc., to obtain the geographic coordinates of the device UE 10 based on the ranging measurement results between the device UE 10 and the anchor UE 14 of the ranging constellation 50. When multiple anchor UEs 14 perform ranging measurements, the ranging measurements may be combined into one report. Note that the device UE 10 may create such a report, as it may perform ranging with all anchor UEs 14. The report may be sent directly to, for example, the RMF 36 and / or LMF 34, or indirectly via the (head) anchor UE 14.

[0169] It should be noted that the LMF 34 and / or RMF 36 may request the anchor UE 14 to provide its known location coordinate information and / or antenna orientation information, if known, to the LMF 34 and / or RMF 36. The antenna orientation information may be used by the LMF 34 and / or RMF 36 to improve the ranging method, e.g., to customize beamforming to improve the calculation of the angle of arrival between the anchor UE 14 and the device UE 10 for a given antenna orientation. Furthermore, the LMF 34 and / or RMF 36 may request the 5GS infrastructure to evaluate the location and orientation of the anchor UE 14. To do so, the anchor UE 14 may have to, for example, measure PRS signals (transmitted by one or more access devices 20) and transmit these measurements to the LMF 34 and / or RMF 36 for location estimation. These measurements may also be used to determine the orientation of the anchor UE. For example, if the anchor UE 14 returns a beamforming configuration (e.g., transmit power, direction) when performing measurements, such as reference signal time difference (RSTD) and / or reference signal received power (RSRP), with one or more different radio access devices 20 (e.g., gNBs), the 5GS infrastructure can determine the orientation of the anchor UE 14. In this case, the radio access device 20 (e.g., gNB) may perform beam sweeping during initial access or broadcasting SSBs or perform beam determination in idle mode (e.g., as described in 3GPP TS38.802 "Study on New Radio Access Technology", V14.2.0, section 6.1.6.1). This allows the gNB to determine the location of the anchor UE 14. Similarly, the anchor UE 14 may transmit, for example, synchronization signals (SS) in multiple directions. The wireless access device can measure the received power of different synchronization signals and, by combining the measurements, calculate the orientation of the anchor UE 14 according to the signals / responses received by the wireless access device 20 (e.g., gNB) from the anchor UE 14 in different beam directions.

[0170] Detailed architecture and procedures for distributed location FIG. 6 illustrates, in accordance with various embodiments, a network architecture in which a mobile terminal (e.g., device UE) 10 approaches a ranging constellation 50 of a mobile terminal (e.g., anchor UE) 14 and is assisted by a ranging service (RS) for location coordinates obtained from a location service (LS).

[0171] In an embodiment related to distributed position location based on ranging measurements with anchor UEs 14, one of the anchor UEs 14 may receive a location (e.g., geographic) coordinate request from the device UE 10 directly or via another device UE close to the ranging constellation 50 and acknowledge the request. The ranging measurements corresponding to the device UE 10 and the ranging constellation 50, i.e., the ranging measurements performed on ranging reference signals between the device UE 10 and one or more anchor UEs of the ranging constellation, may be used by the anchor UE 14 to locally calculate (using any of the concepts described in this disclosure) the location coordinates of the device UE 10 based on its own location information obtained from a location service or an additional location module provided to the anchor UE 14 and the ranging measurements with the device UE 10.

[0172] It should be noted that the anchor UE 14 may also inform the device UE 10 of the local coordinate system used by the ranging constellation 50 and the expected accuracy of a given ranging measurement performed between the device UE 10 and the anchor UE 14. If the ranging constellation 50 supports multiple coordinate systems, the anchor UE 14 may inform the device UE 10 of the different types of coordinate systems supported by the ranging constellation 50. The device UE 10 may select one of the supported coordinate systems or let the anchor UE 14 determine a default coordinate system for that device UE 10 depending on the device characteristics. It should be noted that local coordinates using such coordinate systems may be converted to geographic coordinates by the anchor UE 14 or other device UE 10 that may act as a proxy for a location service or by the location service of the wireless access device 20 or by the LMF 34, RMF 36 or other location or ranging services provided / accessible by the core network upon request of the device UE 10. For this purpose, the ranging-enabled UE may send a message over a secure interface to the LMF 34, RMF 36, or other location and / or ranging service in the core network or provided by the access device, or a proxy of the LMF 34, RMF 36, or other location and / or ranging service provided by another ranging-enabled UE (e.g., anchor UE 14). The message may include distance and / or angle measurements (e.g., based on ranging reference signals), and optionally other information such as ID and / or timing information. Alternatively, the message may include distance and / or angle calculations (e.g., based on ranging measurements), optionally a location coordinate system to use, and optionally altitude and / or speed / accelerometer information. Thus, when the message is received by the LMF 34, RMF 36, or other location / ranging service, or location / ranging service proxy, a response message is returned containing location coordinates calculated using the specified optional location coordinate system or a default (geographical) coordinate system.

[0173] To allow the LMF34, RMF36, or other location and / or ranging service, or a proxy thereof, to calculate a position or distance / angle, the device UE10 may grant authorization by providing authorization credentials to the LMF34, RMF36, or other location and / or ranging service, or a proxy thereof, as part of the same or a subsequent message. The authorization credentials may be used to authenticate / verify that the authorization is genuine (i.e., provided by the device UE10). This may be done, for example, by performing an authentication procedure with the device UE10, or by verifying that the credentials match or are securely associated with credentials of the device UE10 previously stored in the LMF34, RMF36, or other location and / or ranging service, or a proxy thereof, or a core network function (e.g., UDM / AUSF), and / or by providing consent within a subscription (e.g., by UDM) or through a network publishing function (NEF).

[0174] Similarly, using a similar message, which may also include location information or an identifier of the device or reference point, a ranging-enabled UE may request a location and / or ranging service (or its proxy) to provide / calculate / return a distance and / or angle between the ranging-enabled UE and a specified device or reference point. The LMF 34, RMF 36, or other location and / or ranging service (or its proxy) then returns the calculated distance and / or angle.

[0175] In another (alternative) embodiment related to distributed localization based on ranging measurements by anchor UE 14, the ranging constellation 50 may be configured and deployed in an indoor environment or a known target area so that it can have its own local coordinate system relative to a reference geographic coordinate system. A device UE 10 that is in close proximity to the ranging constellation 50 and is authorized to use the ranging constellation 50 may request location coordinates from the anchor UE 14 of the ranging constellation 50. Upon receiving the request, the anchor UE 14 itself, or the head device of the ranging constellation 50 on its behalf, may select at least one (typically two or three) anchor UE 14 of the ranging constellation 50 to perform ranging measurements with the device UE 10. The selected device is the device that is within the required ranging distance from the device UE 10 and can perform ranging with the device UE 10 to calculate the location of the device UE 10 according to the local coordinate system of the ranging constellation 50. The selected anchor UE 14 of the ranging constellation 50 may initiate ranging measurements with the device UE 10, for example in a synchronized or coordinated manner, to obtain ranging measurements. The ranging measurements are used by the head device of the ranging constellation 50, or by a combination of ranging and location services (or their proxies) to determine the location of the device UE 10 in the local coordinate system of the ranging constellation 50. A coordinated manner may mean performing multiple ranging measurements sequentially in time to avoid all measurements being started at the same time and causing mutual interference. It may also mean performing multiple ranging measurements within a relatively short time to obtain accurate results when the device UE 10 is moving.

[0176] It should be noted that, to protect the privacy of the ranging procedure, certain ranging parameters (e.g., constellation identifier, anchor UE identifier, information about the ranging reference signal used by the first UE at a particular time) and / or information (e.g., identifier) ​​embedded / added / multiplexed in the ranging reference signal and / or ranging measurements / results may be transmitted to the second UE only if the second UE is authorized to use the ranging reference signal of the first UE. To prevent tracking of the UE based on the ranging reference signal and / or positioning message broadcast by the UE, the identification information and / or resources (timing / frequency) of the ranging reference signal and / or positioning message may be randomly assigned. For example, the signals / messages may follow a random-looking pattern known only to authorized devices, rather than following a well-known or deterministic pattern (e.g., a periodic pattern of signals / messages transmitted periodically / at a particular time / frequency). Furthermore, after each ranging session, the UE may need to request or receive a new / fresh authentication and / or obtain a new / fresh set of credentials from the core network / access device / RMF / LMF / (head)anchor UE via Uu direct connection or PC5 direct / indirect connection before or during establishing a new ranging session.

[0177] In one example, when the device UE 10 approaches an area and has permission for ranging / location services based on ProSe, it may receive ProSe detection parameters (e.g., ProSe service / application identifier for ranging / location services, or detection key for detecting anchor UEs and / or ranging / location services). Based on these ProSe detection parameters, the device UE 10 may detect other ranging-enabled UEs (e.g., anchor UE 14) present in the area, which may use one of the ProSe detection procedures. Once detection is performed, the anchor UE 14 may provide the ranging / location services requested by the device UE 10 using specific parameters required for ranging / positioning (e.g., positioning signal ID or timing / frequency of positioning signal) using a PC5 secure connection or directly in the detection message itself (e.g., as part of metadata fields). It should be noted that ranging can be performed in multiple ways, as indicated in the first section above. For example, the device UE 10 may have beamforming capabilities so that it can direct ranging measurements to a specific anchor UE 14, and this "angle" information may be used to determine its location.

[0178] In a further (alternative) embodiment related to distributed positioning based on ranging measurements with anchor UEs 14, the device UE 10 may receive an updated list of anchor UEs 14 in its vicinity, for example from the LMF 34 or RMF 36 or other management entity. Note that the LMF 34 and / or RMF 36 or other management entity may create and keep updating the list of anchor UEs 14, so that the constellation of ranging-capable UEs whose locations are known a priori by the LMF 34 and / or RMF 36 or other management entity is always updated. Optionally, to provide control to the network operator, the device UE 10 may be required to report measurements (e.g. values ​​of measurements performed on ranging reference signals received from one or more anchor UEs) to the LMF 34 and / or LMF 36 or other management entity along with the location of the device UE 10.

[0179] It should be noted that if a PC5 interface is required, the device UE 10 and the anchor UE 14 need to discover each other. Therefore, the LMF 34 or RMF 36 or other management entity may need to interface with a network function in the 5G CN (e.g., a Direct Discovery Name Management Function (DDNMF) or a Policy Control Function (PCF)) that can allow the device UE 10 to discover the anchor UE 14 via a (PC5) discovery message.

[0180] When device UE 10 approaches and comes within ranging distance of one of the anchor UEs 14 of the ranging constellation 50, it may be assisted in obtaining its location coordinates through ranging measurements without actually being positioned by the network access device 20 and / or LMF 34.

[0181] In yet another embodiment for distributed location based on ranging measurements with the anchor UE 14, which can be used instead of or in combination with the corresponding embodiment above, the out-of-coverage device UE 10 may request its current location information from a connected anchor UE 14 that is calibrated for ranging measurements with the device UE 10. This may be done, for example, by sending a message including measurements related to the ranging reference signal (such measurements may include, for example, device ID or ranging reference signal ID and / or timing information) and / or estimated distance / angle to the anchor UE 14, and optionally information about the coordinate system used, altitude and / or speed / accelerometer information. The message type (e.g. PC5_Location_Request or RRCLocationRequest) may indicate to the anchor UE 14 that the device UE 10 is requesting location information based on the information provided, which the anchor UE 14 may return (after calculation) to the device UE 10 in a response message.

[0182] Similarly, using a similar message, which may also include location information or device or reference point identifiers, the device UE 10 can request the anchor UE 14 to provide / calculate / return the distance and / or angle between the device UE 10 and the anchor UE 14 and / or a specified device or reference point. The anchor UE 14 then returns the calculated distance and / or angle. The anchor UE 14 knows its own location or can request its own location coordinates based on positioning measurements with the network access device 20 (e.g., gNB) from the LMF 34 or RMF 36 or other location information service of the core network 30 (e.g., network controller device) and convert the ranging measurements of the device UE 10 into the local location coordinates of the device UE 10.

[0183] Alternatively, the anchor UE 14 may report the ranging measurements of the device UE 10 along with its device ID to the LMF 34 or RMF 36. The LMF or RMF may calculate and obtain the location coordinates of the device UE 10.

[0184] Alternatively, the position coordinates of the anchor UE 14 may be shared with the device UE 10, and the device UE 10 may calculate its own position coordinates using the ranging measurements and the position coordinates of the anchor UE 14.

[0185] In yet another (alternative) embodiment related to distributed positioning based on ranging measurements with an anchor UE 14, an anchor UE present in the ranging constellation 50 may be configured to advertise a (ranging-based) positioning service (or a proxy thereof) as a proximity service. Note that this may require allocating a portion of the anchor UE 14 to the ranging proximity service. This may require the LMF 34 or RMF 36 or other management entity to interact with a Direct Discovery Name Management Function (DDNMF) or Policy Control Function (PCF) responsible for allocating detection parameters to UEs. Upon connection, membership, and / or authorization to a proximity service for ranging-based positioning, the device UE 10 may receive detection keys / parameters to access (e.g., via a PC5 sidelink channel) the ranging / positioning service (or a proxy thereof). The device UE 10 may then securely transmit (or receive) a discovery message for the ranging-based positioning service (or a proxy thereof) of the anchor UE 14 of the ranging constellation 50 (e.g., via a PC5 sidelink discovery message).

[0186] The management entity, PCF, AUSF, LMF 34, or RMF 36 may provide the device UE 10 with credentials (e.g., during initial provisioning of ranging / location services for the device UE 10 or during an authentication / connection setup procedure between the device UE 10 and the anchor UE 14, which may include message exchanges between the anchor UE and each network function and then the anchor UE 14 forwarding data to the device UE 10, and / or may include message exchanges between the device UE 10 and each network function via a relay connection via the anchor UE 14). The device UE 10 may use the credentials to securely connect to the ranging / location service (or its proxy) and / or protect data that the device UE 10 transmits to the ranging / location service (or its proxy). Alternatively, the device UE 10, together with the management entity, PCF, AUSF, LMF 34, or RMF 36, may derive the credentials (e.g., a key) based on a pre-configured set of credentials (e.g., root credentials in the SIM, or a session key such as Kamf or Kausf). The credentials may be used to securely connect to the ranging / location service (or its proxy) and / or to protect data that the device UE10 transmits to the ranging / location service (or its proxy).

[0187] Upon receiving (or transmitting) the detection message, the anchor UE 14 of the ranging constellation 50 may reply (or include) location and / or ranging measurements or calculated ranging results depending on its device capabilities. This may be achieved by a detection message or by configuring a lower protocol layer (e.g., the physical (PHY) layer) to initiate transmission of positioning signals, communicating timing and / or frequency and / or identification information of the positioning signals to the device UE 10 (e.g., via a PC5 interface) and collecting UE measurements of the received positioning signals or calculated ranging results based on the measurements via the PC5 interface.

[0188] The anchor UE 14 may provide the device UE 10 with a set of ranging parameters (e.g., timing and identity of positioning signals assigned to the anchor UE 14, or other configuration parameters or required ranging parameters) via direct device-to-device communication or detection (e.g., using sidelink / PC5), e.g., upon successful detection as described in the above embodiment. This approach is useful for device UE 10 that is out of coverage, since the device UE 10 can then only receive these parameters from other ranging-capable UEs via direct device-to-device communication or detection (e.g., using sidelink / PC5). Alternatively, the device UE 10 may receive the ranging parameters of the anchor UE 14 when it joins ranging services and / or location services and / or ranging-based positioning services, e.g., after authentication and authorization.

[0189] In one embodiment, in the case of multiple ranging-capable UEs (e.g., anchor UE 14) that have responded to the device UE 10 with ranging signals (e.g., detection messages) or have spontaneously transmitted ranging signals (e.g., detection messages), the device UE 10 can estimate the distance and / or angle based on timing measurements of each ranging signal (e.g., detection message) and use the estimated distance and / or angle to estimate a location, e.g., by triangulation / trilateration. For this purpose, the UE (e.g., anchor UE 14) transmitting the ranging signal (e.g., detection message) can transmit synchronization signals and / or timing information to the receiving device (e.g., device UE 10). Alternatively or additionally, the timing of the resources scheduled for detection (e.g., sidelink detection pool) or the ranging / ranging signal pool may be used to determine the origination time of the ranging signal (e.g., detection message) transmission. The ranging signal (e.g., detection message) may include time stamp information regarding the time the ranging signal was transmitted, or time difference information (e.g., t4-t1 and / or t3-t2 for FTM-based techniques). The ranging signal (e.g., detection message) may include angle of departure information. The device UE 10 can do the same with a ranging signal (e.g., detection message) to another ranging-enabled UE (e.g., anchor UE 14). Alternatively, if only a few (e.g., one) UE 14 respond to the device UE 10 and / or if the ranging signal (e.g., detection message) includes location and time of departure (TOD) information and the clocks of the device UE 10 and anchor UE 14 are synchronized, the device UE 10 can calculate the distance based only on the ranging signal (e.g., detection message) and estimate its position if sufficient information is available (e.g., if the angle can also be measured and / or if information regarding altitude is provided to / from other UEs). This reduces the need for the device UE 10 to send other messages (eg, specific ranging / position / sounding reference signals) to the anchor UE 14 for positioning information.

[0190] In one embodiment, to improve accuracy, the ranging signal (e.g., detection message) may be transmitted in multiple bands / frequencies, a larger bandwidth may be used, or the ranging reference signal may be co-located / pre-pended / appended to the ranging reference signal. Some or all of the content of the detection message (e.g., IDs of other ranging devices) or a copy thereof may be transmitted as payload / encoded data of the ranging reference signal. Similarly, some or all of the content of the ranging reference signal and / or ID or type or device identification information, e.g., related to the location / sounding signal, may be transmitted as payload / encoded data of the detection message.

[0191] Learn more about ranging using ProSe detection messages In the following embodiments, several ranging-based positioning concepts based on detection messages are described, which can be adapted to use positioning signals transmitted at the PHY layer, e.g., as done in existing positioning techniques or as described in the above embodiments.

[0192] In embodiments related to ProSe Open Detection with ToF measurements or carrier phase based ranging, which may be combined with other embodiments or implemented independently, the detection message in ProSe Open Detection may be extended to include ranging capabilities. This may be achieved by configuring the anchor UE 14 to transmit detection messages according to a predefined timing schedule known to the device UE 10 and synchronizing the devices. The detection message may include an identifier (e.g., Relay Service Code (RSC)) or a service identifier or application code indicating a ranging service, a location service, or a ranging based positioning service (or a proxy thereof). Furthermore, the detection message may be extended to include the (fixed) identity (e.g., L2 identity) of the anchor UE 14 (to enable the device UE 10 to identify the anchor UE 14), the location of the anchor UE 14, and / or positioning information (e.g., the location of the anchor UE or the carrier phase based positioning signal used to send the detection message itself). These detection messages may be protected for integrity using a detection user integrity key (DUIK). Based on this, the device UE 10 may check the integrity of the received detection message, identify the anchor UE 14 that delivered the detection message, identify the ranging service or location service or ranging-based positioning service (or a proxy thereof) based on the identifier, extract distance information from the positioning information, and further extract the timing at which the detection message was received.

[0193] In an embodiment related to restricted detection with round trip time (RTT) ranging, which may be combined with other embodiments or implemented independently, the detection message in ProSe restricted detection can be extended to include ranging capabilities. This can be achieved by extending the first message (i.e., detection message) sent by the device UE 10 to include an identifier (e.g., RSC) indicating a ranging service, a location service, a positioning service based on ranging, and / or a ranging / location request. The device UE 10 is configured to start a timer when the detection message is first sent. The device UE 10 can then receive a response from the anchor UE 14, which may include a position Pa of the anchor UE 14. The position Pa can be verified and decrypted using a detection key received by the device UE 10 after registering with or joining the core network and its services (e.g., DDNMF). The device UE 10 measures the timer upon receiving the response from the anchor UE 14. The value of the timer corresponds to the RTT. The distance to the anchor UE 14 can then be calculated as RTT*c / 2. The device UE 10 may also have received the position of the anchor UE 14 and therefore knows that its position is on the circumference of a circle with a radius of RTT*c / 2 centered at the position Pa of the anchor UE 14.

[0194] It should be noted that the anchor UE 14 may require a significant amount of time to process the message, i.e., to decode and verify the initial detection message sent from the device UE 10. Therefore, the calculation of the RTT should not include the processing time of the anchor UE 14 and / or the time that the anchor UE 14 waits to send a response to the initial detection message (e.g., according to scheduled resources), i.e., the time when no packets are in the air. To remove this processing time and / or waiting time from the measured RTT, the response from the anchor UE 14 may further include information of the processing time and / or waiting time at the anchor UE to process the received detection message and send a response (e.g., time t3-t2 in case of FTM, UE RX-TX in case of RTT measurement based on LTE / NR). This allows the device UE 10 to revise the RTT estimate accordingly. Alternatively, the device UE 10 may utilize the timestamp values ​​of the exchanged messages and / or the timestamps sent separately by the anchor UE 14 in addition to the detection message using normal messages, if the time is measured using a ranging signal (e.g., PRS). The device UE 10 can then use its own timer and timestamp values ​​to subtract the processing time of the anchor UE 14. The device UE 10 can estimate its location using two or more of these measurements. Since the detection message is sent anyway for ProSe / ranging based sidelink devices, including the timing information as part of the detection message avoids the device UE 10 and anchor UE 14 from having to exchange additional measurement reports and also from having to send separate PRS / SRS signals.

[0195] Combination with non-3GPP positioning In other embodiments related to distributed positioning based on ranging measurements with anchor UE 14 that can be used instead of or in combination with the corresponding embodiments described above, anchor UE 14 can use non-3GPP® communication channels (e.g., WiFi®, Bluetooth®, etc.) to monitor and track beacon information (e.g., Service Set Identifier (SSID), signal strength, beacon ID, beacon location, etc.) obtained from broadcast messages of other non-3GPP® base stations (e.g., WiFi® access points or Bluetooth® beacons) in the area to assist and / or improve positioning accuracy and location acquisition time across the ranging constellation. Note that non-3GPP® information may be broadcast by device UE 10 and / or anchor UE 14 depending on device capabilities. This beacon information may be sent to LMF 34 and / or RMF 36 when anchor UE 14 observes the beacon information or when requested by LMF 34 and / or RMF 36.

[0196] The LMF 34 and / or the RMF 36 may be communicatively connected to a non-3GPP® positioning system (e.g., a WiFi® positioning system or a Bluetooth® positioning system) to obtain (geographical) position coordinates based on the beacon information. It should be noted that the non-3GPP® positioning system (e.g., a WiFi® positioning system) may be used when there is a discontinuity in the positioning information system due to lack of coverage, or may be used permanently in addition to the conventional 3GPP® positioning service. The device UE 10 may use prior knowledge of the beacon information obtained from broadcast messages of the non-3GPP® technology (e.g., WiFi® or Bluetooth®) (if available) to assist the ranging service in identifying and tracking the orbital information as described in one of the above embodiments. Furthermore, the beacon information observed by the device UE 10 may be transmitted to the LMF 34 and / or the RMF 36 via the anchor UE 14 of the ranging constellation 50. If the device UE 10 and anchor UE 14 are time synchronized, the timing information of the 3GPP® RAT and the beacon information obtained from the non-3GPP® RAT can be combined to estimate the location of the device UE 10 at a particular time and to assist in trajectory tracking. Alternatively, if the device UE 10 is not time synchronized with any anchor UE, the non-3GPP® beacon information may be linked to the timing of the entire ranging constellation 50 or a particular anchor UE 14. Depending on the application, either the device UE 10 or the anchor UE 14 may calculate the clock time offset after the device UE 10 is time synchronized with the anchor UE 14 and / or the ranging constellation 50.

[0197] Alternatively, two ranging-enabled devices may be capable of supporting 3GPP-based and non-3GPP-based ranging methods and / or may use licensed and unlicensed bands to perform ranging measurements. For example, a device may support time difference of arrival via PC5 / sidelink as a 3GPP-enabled method and may support WiFi FTM (Fine Timing Measurement) measurements or Bluetooth beacons, RTT, carrier phase ranging measurements, or AoA / AoD measurements. A ranging-enabled device may announce support for these non-3GPP ranging methods in a discovery message (e.g., PC5 ProSe discovery message) and / or by sending a message to the other ranging device upon or after establishing a connection between the two ranging-enabled devices. A ranging-enabled device may indicate a priority of all 3GPP and non-3GPP ranging methods that it supports, and / or the device may select a preferred set of ranging methods based on configured policies or environmental / context information, and / or application requirements, and / or accuracy requirements. A ranging-enabled device may use multiple ranging methods simultaneously or sequentially.

[0198] In another embodiment, the device UE 10 may need positioning services from a positioning constellation and an anchor UE 14 may be present in its surroundings. The device UE 10 may be a smart watch and the anchor UE 14 may be a smartphone. The exact location of the anchor UE 14 may be known to a management entity by standard positioning signals transmitted by an access device (e.g., gNB). The management entity may be able to determine the approximate location of the device UE 10 based on the fact that the device UE 10 is within range of the anchor UE 14 and the known location of the anchor UE 14.

[0199] Randomized Ranging Reference Signal In an embodiment related to positioning signals from the anchor UE 14, which may be combined with other embodiments or implemented independently, a configuration entity (e.g., a management entity) may assign the anchor UE 14 a random-looking allocation of positioning signals (e.g., transmission times / schedules, positioning signal IDs, and / or timing / frequency patterns that may not be regular). At time t0, positioning signal p0 is used, at time t1, positioning signal p1 is used, at time t2, positioning signal p2 is used, ..., at time ti, positioning signal pi is used, ..., at time tj, positioning signal pj is used. The positioning signals pi and pj may be randomly or seemingly randomly selected from a set of available positioning signals, identified by positioning signal IDs and whose characteristics are pre-configured by the configuration entity. Also, the resources used to transmit the positioning signals may be randomly or seemingly randomly selected from a set of available resources in the area. Furthermore, the time interval (ti+1-ti) between successive signal transmissions may not be a fixed value. Therefore, it is difficult to track UEs transmitting positioning signals over the sidelink channel, and UEs can only use those positioning signals if they are informed about their timing and ID over time. The positioning signal identities may have a one-to-one or many-to-one relationship with anchor UE identities at a particular time, or may have a many-to-many relationship with a set of anchor UE identities at a particular time. Both the transmitting and receiving UEs involved in ranging using each random-looking positioning signal need to be configured with information about the timing over time, as well as the ID of the positioning signal and / or the ID of the UE. The above positioning signals p1, p2,...,pi may be standard signals (e.g., those defined in TS36.211) or may differ, e.g., in waveform, bandwidth, preamble, carrier, guard band, etc., and / or may include patterns indicative of positioning signal ID or anchor UE ID, and may correspond to different positioning signal IDs or anchor UE IDs at times t1, t2,...,ti.This positioning signal ID or anchor UE ID may be, for example, a pseudo-random sequence (e.g., associated with the positioning signal ID or anchor UE ID at a particular time) that is part of the positioning signal, encapsulated by or transmitted via the positioning signal, or may determine the encrypted / scrambled positioning signal ID or anchor UE ID, or may determine the frequency shift of the positioning signal. The anchor UE ID and / or positioning signal ID may also be used to determine / select the radio resources to be used for transmitting / receiving the positioning signal. For this purpose, the access device or management entity may define resources per position signal ID or per anchor UE ID and provide resource allocation information to the involved UEs (e.g., all UEs that are part of the constellation). The management entity may need to ensure that multiple anchor UEs in close proximity do not interfere with each other. Thus, the management entity may need to assign anchor UE IDs and / or positioning signal IDs to each anchor UE in the area at times t1, t2,..., ti so that they do not collide with each other (e.g., anchor UEs do not use the same radio resource elements at the same time). The management entity can inform the involved UEs (e.g., all UEs in the ranging constellation) of their respective identities using a secure connection or encrypted messages (which only the intended recipient can decrypt). Alternatively, the positioning signal ID or the anchor UE ID may be self-selected by the respective anchor UE 14 (or device UE 10) according to, for example, a pre-configured randomization function (e.g., based on UTC time / system frame number (SFN)). This can be securely shared with the UEs of the constellation, and the involved UEs (e.g., all UEs in the ranging constellation) can inform their respective identities using a secure connection or encrypted messages (which only the intended recipient can decrypt).Alternatively, the positioning signal ID or anchor UE ID may be self-selected by each anchor UE 14 (or device UE 10) according to a pre-configured pseudo-randomization function (e.g., based on UTC time / system frame number (SFN)). This allows the configuration of the pseudo-randomization function to be securely shared with UEs in the ranging constellation, which each UE can use to derive the same identification information.

[0200] In a further embodiment related to the immediately preceding embodiment, the management entity utilizes a random-looking allocation of positioning signals for the admission and revocation of the service. The management entity may distribute, i.e. disclose, the random-looking allocation of positioning signals assigned to the anchor UE 14 only to devices UE 10 that have been authorized to use the service, for example during an initial configuration phase. A particular positioning signal pi among the random-looking positioning signals p1, p2, . . . pi, . . . pj may have a limited validity period, for example a few seconds, minutes, etc. In this case, if the positioning signals pi+1, pi+2, . . . are already configured for the UE 10, the UE 10 may be prevented from using the ranging service (its use may be revoked) by updating the random-looking allocation of positioning signals pi+1, pi+2, . . . of the anchor UE 14 and any other anchor UEs on which the UE 10 may rely. Alternatively, the management entity may disclose to the UE 10 only positioning signals (assigned to the anchor UE) that are valid for a very limited time. This may ensure that the UE 10 will automatically lose access to the service after this limited time has elapsed. The above two alternatives provide a practical way to revoke the use of ranging / location services without having to update the credentials of all relevant devices to reflect the revoked authorization.

[0201] Carrier Phase Based Ranging In an embodiment related to carrier phase based sidelink direction ranging, which may be combined with other embodiments or implemented independently, two or more anchor UEs 14 may transmit positioning signals characterized by very specific carrier signatures over the sidelink. The device UE 10 is strictly time synchronized with the two or more anchor UEs 14 and may receive positioning signals from the two or more anchor UEs, measure the number of carrier cycles CCi of each anchor UE positioning signal after transmission, and derive the distance Di to each anchor UE 14 as Di=CCi*λ, where λ represents the wavelength of the positioning signal, and may estimate its own position P based on the measured Di and knowledge of the location of the anchor UE 14.

[0202] Measuring the number of carrier cycles can be accomplished by decoding and calculating the code in the signal and using phase measurements. Calculating the number of cycles may be based on decoding a known pseudorandom code (PRC) in the signal and looking at what "point in time" the PRC is at for each signal compared to an internal clock reference. From these a rough number of cycles CC can be calculated. The finer part of CC (a fraction of a carrier cycle) can be obtained from carrier signal phase measurements.

[0203] In an embodiment related to ranging based on differential carrier phase, which may be combined with other embodiments or implemented independently, two or more anchor UEs 14 or wireless access devices 20 transmit positioning signals characterized by very specific carrier signatures. An additional anchor UE (e.g., a head anchor UE) is positioned at a known location (e.g., (x,y,z) coordinates) in the ranging constellation 50 and measures the location signals from the other two or more anchor UEs 14 or wireless access devices 20.

[0204] The device UE 10 is strictly time-synchronized with the head anchor UE and the anchor UE 14, receives positioning signals from two or more anchor UEs 14, measures the carriers of the positioning signals, estimates its own position P at time t based thereon, receives from the lead anchor UE a current positioning signal error E_Lead measured by the lead anchor UE at time t (E_Lead=P_Lead-P_REAL, where P_Lead is the position measured by the lead anchor UE based on the carrier phase and P_REAL is the (e.g., pre-configured) actual position of the lead anchor UE), and may obtain an enhanced differential positioning estimate by combining P and E_Lead (because E_Lead is correlated with the error caused by the device UE 10). For example, at time t, the following holds: P_Corrected=P-E_Lead

[0205] In the above, all communication links may be based on a PC5 communication interface between two or more UEs.

[0206] In an embodiment related to ranging based on RTT carrier phase between the device UE 10 and the anchor UE 14 (or the wireless access device 20), which may be combined with other embodiments or implemented independently, the anchor UE 14 (e.g., head anchor UE) (or the wireless access device 20) transmits a positioning signal using a well-defined carrier signal. The anchor UE 14 (or the wireless access device 20) starts counting the number of carrier cycles CC.

[0207] The device UE starts retransmitting (a copy of) the received positioning signal or generates itself a (well-defined) carrier signal immediately after reception and transmits it towards the anchor UE 14 (or wireless access device 20). The device UE 10 may count and transmit the number of carrier cycles CC_delay it took before it starts retransmitting the signal or starts transmitting its own generated carrier signal after it was first received. The anchor UE 14 (or wireless access device 20) stops its counter as soon as it receives the signal from the device UE 10 and reads the value of CC. It can then obtain the distance D between the device UE 10 and itself as follows: D=0.5*(CC-CC_delay)*λ Here, λ represents the wavelength of the carrier signal.

[0208] This embodiment can be expanded by measuring not only the total number of wavelengths of the received carrier, but also the phase of the carrier when the signal is received.

[0209] Furthermore, the anchor UE 14 (or wireless access device 20) may need to wait the length of one carrier cycle to be able to correctly identify the signal returned from the device UE 10. Thus, unless it is able to recognize the signal using a particular preamble, the CC measurement may be too high, perhaps by one carrier cycle, by the time the timer can be stopped. Thus, a preamble may be used to recognize the signal from the device UE 10. A preamble may also be added to allow the device UE 10 to recognize the positioning signal for carrier-based ranging from the anchor UE 14 (or wireless access device 20).

[0210] In one embodiment, which may be combined with other embodiments or implemented independently, the device UE 10 and / or anchor UE 14 (or access device 20) may need to make corrections for the length, location, and orientation of the antenna used to perform the ranging measurement, especially the carrier-phase based ranging. For example, in the case of a car, the antenna may be very long and / or located very far away from the ranging reception / measurement subsystem, the ranging calculation signal subsystem, and / or the subsystem that creates and / or transmits the ranging reference signal. In the case of carrier-phase based ranging, the length of the respective antenna may need to be added to the distance D or otherwise corrected according to the above formula. Similarly, the distance between the transmitting unit of the ranging reference signal and the location of the antenna used to transmit the signal, and the distance between the ranging reception / measurement subsystem and / or the ranging calculation signal subsystem may need to be added to or otherwise corrected. For this purpose, the device UE 10 and the anchor UE 14 (or the access device 20) may exchange information about the antenna configuration, the antenna port (possibly together with information about the signal transmitted through the port), the length of the antenna, the placement / position of the antenna relative to a reference coordinate, and / or the orientation / angle / direction relative to a reference direction or magnetic north (which may be represented by a vector in a coordinate system, etc.) through a discovery message, and / or a connection setup message, and / or a ranging session start message, and / or a configuration message. Information about the antenna port used to transmit the signal may be encoded as part of the ranging reference signal.

[0211] In embodiments related to carrier sensing using multiple carriers, which may be combined with other embodiments or implemented independently, LTE vehicle-to-everything (V2X) communications may be used, supporting single carrier frequency division multiple access (FDMA) and 10 MHz and 20 MHz channels. The channels are divided into 180 kHz resource blocks, each containing 12 subcarriers of 15 kHz. In 5G R16 V2X, the sidelink may operate in frequency range 1 (i.e., FR1, 410 MHz to 7.125 Ghz) and frequency range 2 (i.e., FR2, 24.25 to 52.6 GHz). Transmission may be performed using orthogonal frequency division multiplexing (OFDM). The number of slots and subcarriers per subframe of the OFDM waveform is flexible.

[0212] Considering sensing based on carrier phase, it may be advantageous to use higher frequencies because the wavelengths are shorter and the error in distance measurement is smaller. Furthermore, it may be advantageous to use multiple carriers at different frequencies. If multiple N carriers are used in the positioning signal transmitted at the physical layer, the receiver may measure the received phase of each of the N carriers. Based on the N phase measurements, the receiver can convert the N phase measurements at the N frequencies into a biased range measurement.

[0213] For example, considering a typical Positioning Reference Signal (PRS), the PRS sequence r l,nsIt can be observed that (m) includes transmissions within a particular subcarrier / symbol as defined in 3GPP TTS36.211, where ns is the slot number and l is the OFDM symbol. A pseudo-random sequence is transmitted at the beginning of each OFDM symbol, and the pseudo-random sequence generator is initialized based on ns or the cell identity NCell-ID. Thus, the PRS sequence depends on the frame / slot timing (ns, l) and the physical cell identity. Note that the cell-specific frequency shift is given by NCell-ID mod 6. The effective reuse factor of the existing PRS sequence is 6. When a UE sets itself as an anchor UE or is configured (e.g., by a management entity) as an anchor UE and transmits a PRS sequence, the UE needs to select or be assigned / configured with an identifier so as not to collide with other nearby anchor UEs.

[0214] Furthermore, the PRS sequence is transmitted within predefined positioning subframes grouped by several consecutive subframes called positioning occasions that occur periodically. For example, a positioning occasion may occur every 160, 320, 640, or 1280 subframes (or milliseconds), and the number of consecutive frames may be 1, 2, 4, or 6 (TS36.211). Another existing parameter is the subframe offset that defines the start of the subframe PRS transmission relative to SFN=0. Current positioning techniques perform positioning by identifying the entire PRS sequence.

[0215] In the following embodiment of carrier phase based ranging, the receiver may first identify the PRS itself. This may be based on timing (which frame and slot), frequency (which carrier), identity (identification used to generate the pseudo-random sequence), duration (how many frames the PRS is transmitted in), and periodicity (how many frames the PRS is transmitted in). Since the anchor UE does not have a cell identity like the base station, the UE may use, for example, a randomly selected identity to generate the pseudo-random sequence. The PRS used by the anchor UE may be determined by a management entity. The management entity may also configure the anchor UE with a policy that determines the preferred PRS parameters or PRS signal (including, for example, an alternative PRS signal if the preferred PRS signal is used by another anchor UE nearby). Furthermore, for carrier phase based ranging, the receiver senses the received phase of each carrier at each symbol / resource element used in the PRS signal, e.g., at the beginning of the symbol being used. Because of the definition of the PRS, not all subcarriers are received simultaneously, the receiver can measure the phase of different carriers at different times and derive the received phase as if all carriers were received simultaneously (due to the periodicity of the subcarriers). The receiver can map the measured phases of multiple different subcarriers to a range measurement.

[0216] Note that since multiple carriers are used, the UE may not need all of them. For example, to achieve adequate accuracy, it may be sufficient for the UE to monitor only N' subcarriers, e.g., the first N' subcarriers of the PRS signal. The value N' may be configured by a management entity. Furthermore, reducing the number of subcarriers that need to be tracked reduces the latency and energy consumption of obtaining ranging measurements and, potentially, transmitting ranging-related measurements.

[0217] Furthermore, note that if N' subcarriers are sufficient, and the carriers used for carrier-phase based ranging / positioning are selected to be adjacent to each other, a measurement may be performed every N'*symbol_time seconds to obtain a measurement. For example, if N'=6, a measurement may be performed on the first 6 subcarriers and a second measurement on the next 6 subcarriers.

[0218] Alternatively, for example, an alternating allocation may be performed, e.g. subcarriers i=2n (n=1,...,N') are used for one measurement and subcarriers i=2n+1 (n=1,...,N') are used for the second measurement. Such spacing has the advantage that the carriers are allocated more evenly. On the other hand, if the PRS is transmitted continuously, the ranging estimate may be updated every time a new symbol using a new suitable carrier is received by using a windowing method where the window tracks the last N' suitable subcarriers received. This reduces the delay to the duration of one symbol.

[0219] Other aspects According to one embodiment, which may be combined with other embodiments or implemented independently, an alternative means of determining the angle between two UEs, which may be useful for example with respect to remote controls / televisions, etc., requires the anchor UE to transmit sidelink synchronization signal blocks (SSSBs) via different beams. The UE can measure the received signal strength of each (SSSB) at the anchor UE. This measurement can be used to determine the angle. For example, an anchor UE with an antenna with five beams may be embedded in a television, where beam 1 is perpendicular to the plane of the television, beam 2 has an angle of 45 degrees upwards, beam 3 has an angle of 45 degrees downwards, beam 4 has an angle of 45 degrees leftwards, and beam 5 has an angle of 45 degrees rightwards. The UE can measure the change in signal strength of the anchor UE's SSSBs while, for example, the user presses a button. The change in the received signal strength of the SSSBs is used, for example, to obtain in which direction the user is moving the UE. Note that in this case, when the user presses a button on the UE, a request to transmit a synchronization or positioning signal (in this case SSSBs) may be transmitted over the PC5 interface. The measurements may be sent back from the UE to the anchor UE over the PC5 interface.

[0220] In one embodiment, which may be combined with any of the above embodiments or implemented independently, the UE may request the anchor UE to transmit positioning signals temporarily. The reason is that existing PRS signals transmitted from base stations follow a periodic pattern with low frequency. However, many ranging scenarios may require high frequency PRS signal transmission during a short period of time, such as the above remote control (UE) and TV (anchor UE) example. In this case, the UE may send a resource scheduling request to the anchor UE via the PC5 interface to request the transmission of positioning signals. The (lead) anchor UE may perform resource allocation and coordinate resource allocation with surrounding anchor UEs. For example, a PRS identifier for the anchor UE may be selected so as not to cause interference.

[0221] Process for ranging-based positioning services - Patents.com Fig. 7 shows a schematic signaling and processing diagram for ranging-based positioning services summarizing several operation options according to the above embodiments. In this diagram, information exchange and its direction are indicated by corresponding arrows, processing steps are indicated by blocks, and time progresses from top to bottom in Fig. 7. The locations where processing steps are performed, or the start and end points of information exchange, are indicated by vertical dotted lines below the respective system components. Not all steps are always necessary, and some steps may be performed multiple times for improved accuracy or continuous ranging-based positioning.

[0222] In an initial configuration step S701, the CN configures the anchor UE (A-UE) as such, which may include sending control information for setting, for example, detection parameters, ranging constellation identifiers, positioning signals and parameters, and / or positioning techniques to the anchor UE. In this step, a specific location of the anchor UE may be configured in the anchor UE. This location may also (only) be known to the CN. Then, in a next step S702, the device UE sends a request to the CN to use / subscribe to a ranging-based positioning service. In response, the CN checks whether the device UE is authorized to use this service and, if so, in step S703 provides the device UE with, for example, detection parameters, positioning signal parameters, and / or the (preferred) ranging method to use. This step ends the initial configuration phase (CP).

[0223] The operation phase (OP) starts from step S704, where the device UE sends a discovery message to the anchor UE to request ranging services. This message may be a restricted discovery message (e.g., ProSe Model B Solicitation), or may be skipped in ProSe Model A, or may be a ProSe Model A Announcement, in which the device UE requesting ranging services plays the role of announcing UE. It should be noted that by the time this message is sent by the device UE, the device UE may have first received a sidelink synchronization signal that enables it to synchronize with the anchor UE.

[0224] The anchor UE may collect the presence of received discovery or connection setup or ranging session start messages and / or information from these messages (e.g., UE identification information, ranging capability, timing information, signal strength information) and send to the CN in step S705. In one example, the lead anchor UE may send the aggregate report on behalf of the anchor UEs. Alternatively, each anchor UE may send a received message and be aggregated in the CN.

[0225] In step S706, the CN may estimate the location of the device UE (e.g., a rough initial estimate) based on the (integrated) report received in step S705 and the location of the anchor UE. Alternatively, the CN may perform an initial estimation of the device UE location based on the anchor UE report message received in step S705. Depending on the accuracy of the estimated location, the CN may indicate that a more accurate ranging measurement between the anchor UE and the device UE, e.g., a PRS-based ranging estimation, is required in a subsequent step (see step S707b). In this step, the CN may also check / obtain authorization and / or user consent to use ranging-based positioning services to determine the location of the device UE and / or whether the anchor UE is authorized to participate in this.

[0226] In step S707a, if ProSe restricted detection model B is used, the anchor UE may respond to the device UE with a response message. This message may also indicate that the anchor UE is configured as an announcing UE and uses the ProSe Announcement detection message (model A). The detection message may be used by the device UE for ranging purposes (e.g., directly) or to transmit configuration data required by the device UE to perform ranging in subsequent steps (e.g., if the device UE is out of range and does not initially have positioning parameters transmitted by the anchor UE) and / or to perform an initial position estimation (e.g., if some or all of the message contains location coordinate information for each anchor UE).

[0227] Optionally, a further step 707b may be used in which the CN sends an indication to the anchor UE regarding the achieved or required accuracy. Depending on this indication from the CN, the anchor UE may (re)configure the ranging procedure, e.g. the transmission of PRS signals for ranging-based position estimation. This may mean that the ranging messages of steps S704-S715 may be exchanged longer or shorter, or more frequently and / or with different signal characteristics. This may also mean that the anchor UE skips the ranging procedure (steps S709-S717) if the accuracy obtained in step S706 is already sufficient. If this optional step S707b is not present, the normal flow of ranging steps S709-S717 is performed.

[0228] In step S708, the device UE may obtain an initial range / position estimate based on the message received from the anchor UE in step S707a and possibly the (timing and content of) the message sent in step S704. To increase accuracy, the messages of steps S704 and S707a may be exchanged multiple times.

[0229] In addition, if there are multiple anchor UEs that responded to the device UE in step S707a, and some or all of the response messages contain location coordinate information of each anchor UE, the device UE can estimate its own location by triangulation / trilateration based on these messages received in step S707a.

[0230] In step S709, the anchor UE may transmit one or more positioning signals that are received by the device UE. Then, in step S710, the device UE may perform an estimation of its range / location based on the positioning signals received in step S709. If an initial estimation was performed in step S708, the estimation in step S710 may improve the accuracy of the initial estimation.

[0231] Alternatively, or in combination with the above step S709, the device UE may transmit positioning signals that may be received / measured by the anchor UE in step S711. The lead anchor UE may be responsible for collecting these measurements for the anchor UE.

[0232] In addition, the UE may use other (types of) signals (e.g., Sounding Reference Signals (SRS) or Channel State Information Reference Signals (CSI-RS)) or multiple types of positioning signals in channels specified or requested by the anchor UE to perform more accurate ranging measurements.

[0233] In step S712, the lead anchor UE may locally obtain a location / range of the device UE based on positioning signals received by the lead anchor UE and / or one or more other anchor UEs.

[0234] In step S713, the device UE may transmit measurements and / or calculated distances / angles / positions based on the exchanged detection messages or positioning signals to one or more anchor UEs.

[0235] Then, in step S714, the lead anchor UE may locally obtain the location / range of the device UE based on the measurements reported in step S713 and / or the calculated distance / angle / position. If the location / range of the device UE was already determined locally in step S712, this may be an improved estimate based on the additional information provided by the measurements reported in step S713.

[0236] If the lead anchor UE calculates the location / range of the device UE, the lead anchor UE may transmit this information to the device UE in step S715. Similarly, if another anchor UE calculates the distance to the device UE, it may transmit this information to the device UE in step S715.

[0237] Further, in step S716, the lead anchor UE (or other anchor UE, ranging-capable UE, or relay device) transmits the received measurements to the CN, which may estimate the location / range of the device UE in step S717. Typically, the lead anchor UE transmits these measurements directly via the access device if it is in coverage, but may delegate this task to another UE in the ranging constellation if it is out of coverage, or may transmit these measurements indirectly via a relay device (e.g., a relay UE from a ProSe UE to the network).

[0238] Finally, in step S718, the CN may export the ranging / location information to the external application (AF) after authentication and authorization of the AF.

[0239] Calibrating the Ranging Constellation (Specific to this patent application) In the following, various calibration and / or power saving embodiments are described with reference to Figures 8-10. In these figures, a user device (e.g., device UE) determines the need for calibration and, if the need is confirmed, a calibration procedure may be performed. Additionally / or energy consumption may be optimized (e.g., reduced by lowering accuracy requirements or increased if more accurate ranging is required) or accuracy may be calibrated.

[0240] Note that Figures 8, 9, and 10 show signaling and processing diagrams (similar to Figure 7) where information exchange and its direction are indicated by corresponding arrows, processing steps are indicated by blocks, and time progresses from top to bottom. The locations where processing steps are performed, or the start and end points of information exchanges, are indicated by vertical lines below each system component. Not all steps are required at all times, and some steps may be performed multiple times for improved accuracy or positioning based on successive ranging.

[0241] In one embodiment of the calibration procedure, a (approaching) device UE that is not synchronized with an anchor UE of a ranging constellation may be configured to identify the need for calibration (e.g., timing calibration) for ranging measurements between itself and the anchor UE before performing ranging measurements between them, thereby ensuring high accuracy of the ranging measurements and minimizing errors caused by various sources involved in the ranging measurements, such as lack of frame synchronization, drift of internal clocks, device internal and wireless signal propagation delays, delay spread, Doppler spread, Doppler shift, average wireless transmitter / receiver gain, and / or average delay of the approaching device UE.

[0242] In one embodiment, the need for calibration may be determined based on a synchronization signal transmitted or broadcast by the anchor UE. The approaching device UE may detect the synchronization signal and check if its clock is not synchronized to the anchor UE. This check may be performed, for example, as described in 3GPP specification TS36.211, section 9, "Physical channels and modulation."

[0243] FIG. 8 shows a schematic signaling and processing diagram of a process for identifying the need for calibration according to another embodiment.

[0244] A device UE, configured to approach a ranging constellation and identify itself as needing calibration, transmits a ranging request to an anchor UE (A-UE) at time T1 in step S801. Time T1 refers to the local time of the device UE, i.e., the time based on the local timer or timing system of the device UE. It is assumed that the clocks of the device UE and the anchor UE are not synchronized with each other and may be connected to different base station devices (e.g., gNBs) that may belong to different network operators.

[0245] When the anchor UE receives the ranging request at time T2, in step S802, it sends an acknowledgment to the approaching device UE at time T3, where times T2 and T3 refer to the local time of the anchor UE, and the local time is based on the local clock, timer, or timing system of the anchor UE.

[0246] At local time T4 of the approaching device UE, the device UE receives an acknowledgment indicating local times T2 and T3 at the anchor device. Based on this information, the approaching device UE can calculate the timing error (i.e., the time difference between the local clocks on the device UE and the anchor UE) in step S803 using the following formula: Timing error = {(T2-T1)-(T4-T3)} / 2

[0247] We need to divide by two because the timing error includes a first clock drift on the forward path (i.e., sending the ranging request packet / message) and a second clock drift on the reverse path (i.e., receiving the acknowledgment packet / message). In other words, the time measurement is affected twice by the same clock drift.

[0248] To limit the error of the ranging estimation, a configurable threshold for the timing error may be set in the approaching device UE. For example, the threshold may be identified based on the required ranging accuracy (e.g., a maximum allowed timing error of 1 ns corresponding to a ranging accuracy of 33 cm) for a particular device configuration (e.g., including but not limited to the latest known cell ID, the latest known synchronization source, and / or the current synchronization source) of the approaching device UE and its properties (e.g., including but not limited to the operating frequency, radio transmit power, local clock properties, estimated local clock drift, and / or antenna properties) of the approaching device UE. This threshold may also be set in the acknowledgement packet by the anchor UE based on the device properties and the ranging configuration. Alternatively, the ranging service corresponding to the approaching UE may determine the threshold required to perform the ranging measurement with a certain accuracy.

[0249] In step S804, the approaching device UE determines whether the timing error calculated in step S803 is higher than a configurable threshold for the timing error, for example based on a comparison operation, thereby identifying whether a timing calibration needs to be performed.

[0250] If in step S804 the approaching device UE determines that the calculated timing error is less than the timing error threshold, then the procedure branches to step S805a, where one or more ranging measurements are performed between the approaching device UE and the anchor UE (or another UE in the ranging constellation). For example, if the clocks of the device UE and the anchor UE are synchronized, the estimated time of flight may be calculated as follows: Estimated flight time = {(T2-T1)+(T4-T3)} / 2

[0251] An alternative condition for performing a ranging measurement may be that the timing error is much smaller than the estimated time of flight.

[0252] As a supplemental option, a final estimated flight time may be calculated as a function of the estimated flight time and the timing error, F. For example, F may be the estimated flight time minus the timing error, as follows: Final estimated flight time = estimated flight time - timing error

[0253] Otherwise, if the approaching device UE determines that the timing error calculated in step S804 is greater than or equal to the timing error threshold, the procedure branches to step S805b where the calibration process is initiated.

[0254] According to a first example of the calibration process of step S805b, the device UE may use the received synchronization signal to synchronize its local clock, the timing of transmitted frames / slots, and other communication parameters (e.g., its carrier frequency).

[0255] According to a second example of the calibration process in step S805b, the approaching UE may transmit the determined timing error to the anchor UE in step S806 to request a timing synchronization procedure. This procedure may be performed over the PC5 interface, for example using a Primary Sidelink Synchronization Signal (PSSS) and / or a Secondary Sidelink Synchronization Signal (SSSS) from the anchor UE or another device UE, as described in section 9 of the 3GPP specification TS36.211 "Physical channels and modulation".

[0256] FIG. 9 illustrates generally a signaling and processing diagram of a calibration process according to an embodiment in which calibration is performed based on calibration requirements and a synchronization schedule is configured.

[0257] In step S901, a synchronization signal from an anchor UE (A-UE) is received by an approaching device UE. Based on the received synchronization signal, the approaching device UE compensates for a timing error using a timing correction or compensation value determined based on the synchronization signal in step S902.

[0258] The synchronization signal may include, among other things, an unmodulated carrier, and phase and timing information corresponding to the synchronization signal. The device UE may locally generate a similar waveform using the timing and phase information obtained from the synchronization signal. For example, the device UE may locally generate a signal C_SIGN using its internal clock, which may be expressed as a function of the timing error, phase error, and the synchronization signal S_SIGN as follows: C_SIGN(t,φ)=S_SIGN([t±td],[φ±φd])*Tcv Here, t denotes the time period of the observed signal, td denotes the estimated positive or negative drift rate of the internal clock relative to the synchronization signal, φ denotes the phase angle of the observed signal, φd denotes the phase difference between the internal clock and the synchronization signal, and Tcv denotes the timing correction value.

[0259] The timing corrections may be calculated using the formula shown below and may be used to compensate for timing errors caused by propagation and / or computation delays that are very similar in both devices at a given time and in the short range measurement environment. The estimated timing corrections may be calculated as follows: Tcv={C_SIGN(t,φ)-S_SIGN(t,φ)} / {S_SIGN(t,φ)}

[0260] In step S903, a timing compensation value for offsetting the timing error in the approaching device UE is updated.

[0261] In step S904, a ranging procedure involving ranging measurements is performed. However, it should be noted that the update process of step S903 may be performed periodically throughout the entire duration of the ranging measurements of step S904 until there is no timing error or it is below the minimum acceptable timing error at the approaching device UE.

[0262] In one example, the calculation of the periodic schedule may be performed locally by a ranging service on the device UE or via an RMF of a core network corresponding to the anchor UE.

[0263] In another example, any (anchor) UE belonging to a ranging constellation may request a management entity of the ranging constellation (e.g., on the head anchor UE) to calculate and perform a synchronization schedule on behalf of an approaching device UE, provided that it is within the ranging distance of the head anchor UE of the constellation. As another option, the device UE may be part of the ranging constellation and request the anchor UE to perform this on its behalf.

[0264] In a further example, the device ID and connection parameters of the approaching device UE may be shared with the designated head anchor UE by the anchor UE.

[0265] In yet another example, an approaching device UE may request the anchor UE to increase or decrease the period of a broadcast or synchronization signal, i.e., generally, to adjust its synchronization schedule. For example, if the anchor UE transmits a synchronization signal over sidelink communication every 160 milliseconds, the device UE may instruct the anchor UE to transmit the synchronization signal more or less frequently, as needed.

[0266] Alternatively, the schedule may be determined and configured, for example, based on the device properties, ranging accuracy requirements, and / or timing errors of the approaching device UE, and transmitted via a secure channel setup between the approaching device UE and the anchor UE. As a result, the period of the broadcast signal or the synchronization signal is increased or decreased. As an additional option, the timing offset value identified in the clock synchronization process may also be used to calculate the period of the synchronization signal. This configuration may be performed directly via the PC5 interface or via the serving base station device (e.g., gNB).

[0267] Optionally, upon completion of the ranging service performed between the approaching device UE and the anchor UE in step S904, synchronization of the device UE is stopped by the anchor UE in step S905, and resources used for the synchronization process are released and can be used for other purposes.

[0268] In one example, a timeout value may be set, after which the synchronization process of the ranging service for the approaching device UE may be automatically stopped.

[0269] In one example, if an approaching device UE is out of coverage, the device UE can encode a ranging request over the PC5 interface, for example using a discovery message, so that an anchor UE within range of the device UE can choose whether or not to acknowledge the discovery message and communicate with the device UE depending on its ranging capabilities or the properties of the request message. In response to an acknowledgement from the anchor UE, a process similar to that described above can be performed to process and calibrate the ranging request.

[0270] Depending on the type of positioning method used to estimate position and / or distance, any of the above identification, calibration, and verification may be extended using other configuration parameters (e.g., timing, phase, and frequency).

[0271] FIG. 10 shows a schematic signaling and processing diagram of a centralized calibration process according to an embodiment, in which the optimization and configuration of the ranging procedure is performed centrally.

[0272] In step S1001, a management entity (e.g., a base station or a core network device / function) may monitor the resource capabilities (e.g., energy availability, power class, transmission range, bandwidth, etc.) of anchor UEs in a geographic area, and enable device UEs located near a ranging constellation to use only ranging services or to preferentially use ranging services. This can save power consumption when device UEs request their location, since location-based service support typically requires more power than ranging services alone.

[0273] Thus, in step S1002, the management entity can assign an anchor UE to the device UE to optimize one or more parameters, for example: i. Optimize (minimize) the energy consumption of the ranging process by selecting the closest anchor UE and keeping the transmission power as low as possible; ii. Optimize the ranging accuracy by selecting a more distant anchor UE but using a more accurate ToF based ranging procedure (since the ToF value is larger when the selected anchor UE is at a larger distance). More specifically, a higher ToF value may lead to higher accuracy since other sources of timing inaccuracies such as clock drift are better hidden.

[0274] As a further option, in step S1003, the management entity may configure the device UE to perform ranging in a specific direction or distance, for example via beamforming, such that ranging is performed only by a selected group or class of devices. This allows the ranging service to be highly accurate but without increasing power consumption, and / or ranging measurements may not be performed randomly by various devices with specific ranging requirements. Other ranging parameters (e.g., including but not limited to repetition frequency, transmission range, and transmission power, etc.) may be set by the management entity based on the current resource availability of the device UE and / or the availability of other ranging devices and ranging constellations in the vicinity of the device UE.

[0275] As yet another option, the management entity may set certain policies in the device UE in step S1004 so as to control the operation between the device UE and the anchor UE depending on the received synchronization and / or positioning and / or ranging signals. Examples of policies that may be set may be: - A policy indicating that if at least one ranging constellation with at least three anchor UEs located at a distance less than the configured threshold Dmax is nearby, then use the ranging constellation to determine location, otherwise use location services. - A policy indicating that the device UE may request the anchor UE of the used ranging constellation to transmit synchronization signals with a periodicity of once every N ms (e.g., N=320 ms) if the determined timing error exceeds a threshold T (e.g., 5 ns), but not to request a change in the periodicity of these signals otherwise.

[0276] In another embodiment, a management entity (here, which may be a user of the approaching device UE) may use an application programming interface (API) (e.g., NEF for accessing the CN) of the network and / or base station device to set target ranging and positioning accuracy and target energy consumption (e.g., expressed as UE battery life or as average power consumption in milliwatts) for a particular device UE or a group of devices UE, so that the core network (e.g., network controller) can change parameters affecting accuracy and / or energy consumption (e.g., but not limited to, update interval of ranging values, sampling frequency of ranging, periodicity of time synchronization signal, and / or resource allocation for the device UE) via the base station device.

[0277] In summary, a wireless system and method for managing and / or configuring two or more ranging-enabled devices to form a ranging constellation supporting ranging-based positioning services has been described. Additionally, challenges in determining the need for calibration of the ranging services for improved accuracy and / or reduced power consumption have been addressed.

[0278] While the present invention has been illustrated and described in detail in the drawings and above, such illustration and description should be considered as illustrative or exemplary and not restrictive. The present invention is not limited to the disclosed embodiments. The proposed ranging-based enhanced positioning service can be implemented in any kind of wireless network, for example in accordance with cellular wireless communication standards, in particular 3GPP (registered trademark) (3GPP). rdThe 5G wireless communication device may be applicable to devices that communicate using the 5G (5G Generation Partnership Project) specification and the New Radio (NR) specification. The 5G wireless communication device may be of various kinds, such as a mobile phone, a smart watch, a smart tag for location tracking and logistics, a vehicle (for vehicle-to-vehicle (V2V) communication or more general vehicle-to-everything (V2X) communication), a V2X device, an IoT hub, an IoT device (including low-power medical sensors for health monitoring), a medical (emergency) diagnostic and treatment device (for hospitals or first responders), a virtual reality (VR) headset, etc.

[0279] Although some embodiments are described for ProSe relay and sidelink communication, the invention also applies to other types of relay devices, such as (smart) repeater devices, Integrated Access and Backhaul (IAB) nodes, or WiFi mesh APs.

[0280] Furthermore, the present invention is applicable to medical applications or connected healthcare where multiple wireless (e.g., 4G / 5G) connected sensor or actuator nodes participate, medical applications or connected healthcare where wireless (e.g., 4G / 5G) connected equipment consumes or generates continuous data streams at certain average data rates from time to time (e.g., video, ultrasound, x-ray, computed tomography (CT) imaging devices, real-time patient sensors, audio or voice or video streaming devices used by medical staff), general IoT applications (e.g., smart cities, logistics, agriculture, etc.) involving wireless, mobile or fixed sensor or actuator nodes, emergency service applications and critical communication applications, V2X systems, systems for improving the coverage of 5G cellular networks using high frequency (e.g., mmWave) RF, and other application areas of 5G communications where relays are used.

[0281] From the drawings, the disclosure, and the appended claims, other variations of the disclosed embodiments can be understood and realized by those skilled in the art practicing the claimed invention. In the claims, the term "comprises" does not exclude other elements or steps, and the indefinite article "a" or "an" does not exclude a plurality. The above description details certain embodiments of the present invention. However, no matter how detailed the above is, it will be understood that the invention can be implemented in many ways and is therefore not limited to the disclosed embodiments. It should be noted that the use of a particular term in describing a particular feature or aspect of the present invention should not be interpreted as meaning that the term has been redefined to be limited to include the specific features of the feature or aspect of the invention with which it is associated. Furthermore, those skilled in the art will generally understand that the terms used in this specification, and particularly in the appended claims, are generally intended as "open" terms. For example, the term "comprises" should be interpreted as "including, but not limited to," the term "having" should be interpreted as "having at least," and the term "comprises" should be interpreted as "comprising, but not limited to." Moreover, one of ordinary skill in the art will understand that if a particular number of introduced claim recitations is intended, such intent will be expressly recited in the claim, and that in the absence of such recitation, no such intent exists. For example, to aid in understanding, the following appended claims may include the use of introductory phrases such as "at least one" or "one or more" to introduce claim recitations. However, the use of such language should not be interpreted as meaning that the introduction of a claim recitation with the indefinite article "a" or "an" limits a claim that includes such introduced claim recitation to implementations that include only one such recitation. The same applies when the same claim includes an introductory phrase such as "one or more" or "at least one" and an indefinite article such as "a" or "an," for example, "a" and / or "an" should be interpreted to mean "at least one" or "one or more."The same is true when definite articles are used to introduce claim recitations. Furthermore, when idiomatic expressions similar to "at least one of A, B, and C, etc." are used, such syntax is generally intended in the sense that one of ordinary skill in the art would understand the idiomatic expression, for example, "a system having at least one of A, B, and C" includes, but is not limited to, systems having only A, only B, only C, A and B together, A and C together, B and C together, and / or A, B, and C together. When idiomatic expressions similar to "at least one of A, B, or C, etc." are used, such syntax is generally intended in the sense that one of ordinary skill in the art would understand the idiomatic expression, for example, "a system having at least one of A, B, or C" includes, but is not limited to, systems having only A, only B, only C, A and B together, A and C together, B and C together, and / or A, B, and C together. Additionally, those of skill in the art will understand that virtually any disjunctive word and / or phrase presenting two or more alternative terms, whether in the specification, claims, or drawings, contemplates the possibility of including one of the terms, either term, or both terms. For example, the phrase "A or B" will be understood to include the possibilities of "A" or "B" or "A and B."

[0282] A single unit or device may fulfill the functions of several items recited in the claims. The mere fact that several measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage.

[0283] The described operations, such as those shown in Figures 7 and 10, may be implemented as program code means of a computer program and / or as dedicated hardware in the commissioning device or luminaire device, respectively. The computer program may be stored and / or distributed on a suitable medium, such as an optical storage medium or a solid-state medium, supplied together with or as part of other hardware, or distributed in other forms, such as via the Internet or other wired or wireless telecommunications systems.

Claims

1. 1. An apparatus for providing a location estimate for a target mobile device in a wireless network, the apparatus comprising: determining a timing difference between the target mobile device and an anchor device of a ranging constellation used to support positioning services provided within the wireless network; The apparatus initiates a calibration procedure upon detecting that the timing difference exceeds an upper threshold.

2. The apparatus of claim 1 , wherein the apparatus receives a synchronization signal from the anchor device and detects the timing difference based on the synchronization signal.

3. The device of claim 2 , wherein the device performs the calibration procedure using the received synchronization signal to adjust at least one communication parameter.

4. The apparatus of claim 2 , wherein the apparatus corrects the determined timing difference using a timing correction value determined based on the synchronization signal.

5. The apparatus of claim 4 , wherein the apparatus periodically updates the timing corrections during ranging measurements until the determined timing difference reaches a lower threshold level.

6. 2. The apparatus of claim 1, wherein the apparatus transmits a ranging request to the anchor device, receives an acknowledgment from the anchor device in response to the ranging request, and calculates the timing difference based on a local transmit time and a receive time of at least one of the ranging request and the acknowledgment.

7. The apparatus of claim 1 , wherein the apparatus provides a threshold level that is configurable by a ranging service of the ranging constellation or by a user or application of the target mobile device.

8. 2. The apparatus of claim 1, wherein the apparatus transmits a ranging request to the anchor device, measures a round trip time taken for the ranging request to be acknowledged by the anchor device, and calculates a ranging distance based on the measured round trip time, provided that the timing difference does not reach the threshold level.

9. 2. The apparatus of claim 1, wherein the apparatus transmits the determined timing difference to the anchor device to request a timing synchronization procedure over a sidelink interface.

10. The apparatus of claim 1 , wherein the apparatus requests the anchor device to adjust a synchronization schedule based on the determined timing difference.

11. 1. An apparatus for providing a position estimate for a target mobile device in a wireless network, the apparatus monitoring a resource capability of at least one of a plurality of anchor devices of a ranging constellation and, based on the monitored resource capability, reducing power consumption by selecting at least one of the plurality of anchor devices, limiting a position determination including ranging and positioning services to ranging services, or limiting the ranging services to a particular direction or distance.

12. The apparatus of claim 11 , wherein the apparatus selects an anchor device of the ranging constellation that is located more than a minimum distance away from the target mobile device to improve ranging accuracy.

13. 12. The apparatus of claim 11, further comprising: stopping a calibration procedure between at least one of the plurality of anchor devices and the target mobile device upon completion of a requested ranging service or after a configurable timeout value has elapsed.

14. A network device comprising an apparatus according to any one of claims 1 to 10 or an apparatus according to any one of claims 11 to 13.

15. A system comprising at least one first network device comprising an apparatus according to any one of claims 1 to 10 and at least one second network device comprising an apparatus according to any one of claims 11 to 13.

16. 1. A method for obtaining a location estimate for a target mobile device in a wireless network, the method comprising: determining a timing difference between the target mobile device and an anchor device of a ranging constellation used to support positioning services provided within the wireless network; and initiating a calibration procedure upon detecting that the timing difference exceeds a threshold.

17. 1. A method for obtaining a location estimate for a target mobile device in a wireless network, the method comprising: monitoring resource capabilities of at least one of a plurality of anchor devices of a ranging constellation; and reducing power consumption by selecting at least one of the plurality of anchor devices based on the monitored resource capabilities, or limiting location determination including ranging and positioning services to ranging services, or limiting the ranging services to a particular direction or distance.

18. 1. A method for an apparatus supporting ranging, the method comprising: determining whether the device can function as an anchor device based on a set of criteria; the device performing a series of measurements on the received RF signals to determine or retrieve its location; said device determining whether its location is sufficiently stable and / or whether it is within the coverage of an access device according to said set of policies / criteria; The method includes the step of the device initiating operation as an anchor device based on at least the determination of the previous step, and / or initiating a procedure to request to become an anchor device and / or to be configured as an anchor device.

19. 20. The method of claim 18, wherein the device ceases operating as an anchor device when it determines that there is a predetermined number of other anchor devices in its vicinity.

20. The method according to claim 18 or 19, wherein the device stops operating as an anchor device when it determines that the coverage of location-based services is sufficient according to a location quality threshold at its current location.

21. 1. An apparatus supporting ranging, the apparatus comprising: A communication unit; a processor unit coupled to a memory unit, the memory unit comprising: determining, by the device, whether the device can function as an anchor device based on a set of criteria; the device performing a series of measurements on the received RF signals to determine or derive its location; determining whether the device's location is sufficiently stable and / or within the coverage of an access device according to the set of policies / criteria; The method includes instructions for the device to initiate operation as an anchor device based on at least the determination of the previous step and / or initiate a procedure to request to become an anchor device and / or to be configured as an anchor device.

22. A computer program comprising code means for generating the steps of the method according to claim 16 or claim 17 when said computer program is executed on a computing device.

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