Enhanced ranging and positioning services in wireless networks - Patents.com

Abstract

The present invention relates to a wireless system and method for configuring ranging capable devices to form a ranging constellation to support ranging-based positioning services. The present invention addresses several challenges in improving location accuracy when using ranging measurements to derive location coordinates. In particular, it describes when location information may be derived from ranging measurements and the methods used for ranging-based location estimation.

Description

[Technical field]

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

[0002] Ranging is a process in which the distance and / or angle between two wireless devices is measured as a function of radio parameters (e.g., signal quality, channel conditions, round trip time, etc.). In wireless systems, the accuracy of the ranging measurement is a direct correlation of the link quality of the radio channel used, the calibration of the ranging procedure used, or the hardware capabilities of the device used, in terms of antenna design, energy, and compute resources. In addition, the power consumption of the ranging procedure is a direct correlation of the operation frequency, duty cycle, and repetition of messages from a device to a ranging service of another device. This direct correlation with dynamic system parameters makes the accuracy and power consumption of ranging in wireless devices unpredictable and often adversely 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 crucial in determining the exact location coordinates.

[0003] Wireless standards provide standardized techniques to support peer-to-peer ranging, the requirements of which are specified by several use cases, as described, for example, in 3GPP® specification TR22.855, “Study on Ranging-based Services.” However, challenges remain in improving location services using specific ranging constellations. Summary of the Invention [Problem to be solved by the invention]

[0004] It is an object of the present invention to provide an improved ranging-based location estimation for deriving location information from ranging measurements. [Means for solving the problem]

[0005] This object is achieved by an apparatus according to claim 1, a mobile communication device or access device according to claim 15, a system according to claim 17, a method according to claim 21 and a computer program product according to claim 22.

[0006] According to a first aspect, there is provided an apparatus (e.g., in a mobile communications device or an access device) for obtaining a location estimate of a target mobile device in a wireless network, the apparatus comprising: requesting ranging services from a ranging constellation formed by one or more ranging capable anchor devices of the wireless network, the ranging constellation acting as a proxy for positioning services provided in a geographic area; receiving at least one response message from a ranging constellation; performing a range or location estimation based on the at least one response message; and Calculating a location of the target mobile device based on the range or location estimate or ranging measurements, or forwarding the results of the range or location estimate or ranging measurements to a ranging constellation to support positioning services. The device is adapted to:

[0007] As an alternative to the first aspect, there is provided an apparatus (e.g., in a mobile communications device or access device) for obtaining a location estimate of a target mobile device in a wireless network, the apparatus comprising: - requesting ranging services from a ranging constellation formed by one or more ranging-enabled anchor devices of a wireless network, the ranging constellation acting as a proxy for positioning services provided in a geographical area; - transmitting a ranging reference signal that can be received by an anchor UE of the ranging constellation (e.g., the anchor UE of the ranging constellation performs ranging measurements on the received ranging reference signal and calculates a distance, angle, or location estimate); receiving at least one response message from a ranging constellation (e.g., including a calculated range, angle, or location estimate); The device is adapted to:

[0008] According to a second aspect there is provided a mobile communications or access device comprising the apparatus of the first aspect (or an alternative thereof).

[0009] According to a third aspect, there is provided a system comprising at least one device of the second aspect, wherein positioning services are performed by a wireless access device or by a core network of the wireless network, and anchor devices forming the ranging constellation and participating in the requested ranging service are configured to transmit and / or receive configuration parameters from the wireless access device or the core network.

[0010] According to a fourth aspect, there is provided a method of obtaining a location estimate for a target mobile device in a wireless network, the method comprising: requesting ranging services from a ranging constellation formed by one or more ranging capable anchor devices of the wireless network; receiving at least one response message from a ranging constellation; performing a range or location estimation based on the at least one response message; calculating a location of the target mobile device based on the range or location estimate or ranging measurement, or forwarding the range or location estimate or ranging measurement to a ranging constellation to support positioning services; has.

[0011] Finally, according to a fifth aspect there is provided a computer program product comprising code means for producing the steps of the above method according to the fourth aspect when executed on a computing device.

[0012] Thus, a management entity (e.g., a wireless access device, a base station, or a network function in a core network) configures one or more network devices (e.g., UEs) as anchor devices to form a ranging constellation to support ranging services, location services, and / or ranging-based positioning services (i.e., a combination of ranging and location services functions). This allows for improved location accuracy by locally or centrally coordinating simple ranging measurements between devices. In addition to improving localization and ranging accuracy, ranging constellations also help to reduce power consumption of the involved (mobile) network devices by combining ranging and location services. In particular, the time points at which location information may be derived from ranging measurements and the method used for ranging-based location estimation may be determined.

[0013] The ranging service, location service, and / or ranging-based positioning service that collects ranging measurements is provided by another network other than the wireless network. This service may also be a third-party application that calculates a location based on these measurements. Furthermore, the geographic area of ​​the positioning service depends on the capabilities of the anchor device and / or the characteristics of the environment in which the anchor device is configured. The geographic area of ​​the positioning service does not need to be known a priori by the network and is optionally configurable.

[0014] According to a first option, which can be combined with any of the above first to fifth aspects (including the alternatives mentioned above), the range or location estimation or ranging measurement is performed based on discovery messages or carrier phase based ranging or positioning techniques. The discovery messages allow for integrity protection, scrambling protection and confidentiality protection, and the ranging application used can be identified by using an identifier. The carrier phase based techniques allow for the combination of calculations (from signal decoding) and phase measurements, improving the accuracy of the ranging based location estimation.

[0015] According to a second option, which can be combined with the first option or any of the above first to fifth aspects (including the above-mentioned alternatives), a positioning signal is transmitted to a target mobile device or anchor device by using a predetermined carrier signal, carrier cycles of the carrier signal are counted until a response is received from the target mobile device or anchor device, and a distance to the target mobile device or anchor device is determined based on the counted number of carrier cycles. Thus, the carrier signal of the positioning signal can be directly used to determine the distance to the target mobile device.

[0016] According to a third option, combinable with the first or second option or with any of the above first to fifth aspects (including the above-mentioned alternatives), the apparatus of the second aspect is adapted to initiate self-configuration of a ranging capable anchor device. Thus, upon self-configuration as an anchor device, the target mobile device can directly start announcing discovery messages for distance-based positioning as a proximity service and / or can start transmitting ranging reference signals.

[0017] According to a fourth option, which can be combined with any of the first to third options or any of the above first to fifth aspects (including the above-mentioned alternatives), a switch is performed from determining location coordinates of the target mobile device by a location service to determining location coordinates by a ranging constellation based on ranging measurements, whereby the ranging measurements can be used to improve available location or ranging services provided by the network.

[0018] According to a fifth option, combinable with any of the first to fourth options or any of the first to fifth aspects above (including the alternatives mentioned above), the location coordinates of the target mobile device are obtained from an anchor device of a ranging constellation, the location coordinates being determined by using a set of ranging measurements. Thus, the location coordinates may be obtained directly from the ranging constellation without accessing a core network of the wireless network.

[0019] According to a sixth option, combinable with any of the first to fifth options or with any of the above first to fifth aspects (including the alternatives mentioned above), ranging or sidelink based positioning is performed between the target mobile device and one or more anchor devices of the ranging constellation or between anchor devices of the ranging constellation. This allows performing ranging using sidelink resources and utilizing the resulting measurements to improve the accuracy of the positioning service. The sidelink based positioning is used to determine a location based on ranging using sidelink resources (e.g. by an anchor device or a ranging based positioning service).

[0020] According to a seventh option, combinable with any of the first to sixth options or any of the first to fifth aspects above (including the alternatives mentioned above), at least one of sending an identifier to the target mobile device or another range capable anchor device used to obtain location coordinates from a location service or database, providing authorization credentials to the target mobile device or another anchor device, providing an authorization message or credentials to the location service or database, and granting permission for obtaining by providing consent within a subscription or through a network publishing feature is performed, whereby location coordinates of the target mobile device or another range capable anchor device can be obtained securely from the location service or database.

[0021] According to an eighth option, combinable with any of the first to seventh options or any of the first to fifth aspects above (including the alternatives mentioned above), a number of anchor devices, a set of identifiers of the number of anchor devices, and / or a constellation identifier are indicated as part of at least one message for requesting a ranging session. Thus, the ranging request can be used to provide information for allocating a ranging constellation.

[0022] According to a ninth option, which can be combined with any of the first to eighth options or any of the first to fifth aspects above (including the alternatives mentioned above), a list of approved constellation identifiers and / or ranging capable anchor devices that can be selected for ranging services is provided, thus making access to ranging constellations more efficient.

[0023] According to a tenth option, combinable with any of the first to ninth options or any of the first to fifth aspects above (including the alternatives mentioned above), at least one policy is provided specifying requirements on a minimum number of anchor devices and / or capabilities and / or characteristics of anchor devices for determining whether to request ranging services or for determining which constellation or set of ranging capable anchor devices to select / connect for ranging services, such that the formation and selection of suitable ranging constellations can be controlled via the corresponding policy.

[0024] According to an eleventh option, combinable with any of the first to tenth options or any of the first to fifth aspects above (including the alternatives mentioned above), the apparatus of the first aspect is adapted to be configured by a management entity or to configure itself to switch on the ranging service upon entering a geographical area or upon a target mobile device entering the geographical area, thereby allowing to control access to the ranging service based on a specific geographical area.

[0025] According to a twelfth option, which can be combined with any of the first to eleventh options or any of the first to fifth aspects above (including the alternatives mentioned above), the signal quality or distance measurement results are used to determine whether to initiate a ranging service, determining that the target mobile device is sufficiently close and / or has line of sight with at least one of the ranging capable anchor devices. Thus, the initiation of the ranging service can be controlled to ensure that the anchor devices of the ranging constellation are within operating range.

[0026] According to a thirteenth option, which can be combined with any of the first to twelfth options or any of the first to fifth aspects above (including the alternatives mentioned above), the range or location estimate or ranging measurement is corrected for the length, position and / or orientation of at least one antenna used to perform the ranging measurement, thereby making it possible to prevent or at least reduce measurement errors caused by antenna positioning.

[0027] According to a fourteenth option, combinable with any of the first to thirteenth options or any of the first to fifth aspects above (including the alternatives mentioned above), in response to receiving configuration parameters or desired parameter values ​​to be used that conflict with configuration parameters received from a management entity having a higher priority, the ranging request, the measurement result and / or the calculated distance and / or angle are discarded, an error message is generated, the configuration parameters are updated or an exception is requested to the management entity having a higher priority, thereby allowing conflicts between management entities to be addressed.

[0028] According to a fifteenth option, combinable with any of the first to fourteenth options or with any of the first to fifth aspects above (including the alternatives mentioned above), the wireless access device or the core network is configured to control the at least two mobile communication devices to initiate a ranging session without a discovery phase, the wireless access device or the core network is configured to provide configuration parameters such that each of the at least two mobile communication devices knows how to perform the requested ranging service. Thus, the ranging session can be initiated directly in an efficient manner without prior discovery. According to a sixteenth option, combinable with any of the first to fifteenth options or with any of the first to fifth aspects above, the ranging capable anchor devices of the ranging constellation are provided with a specific relay service code or service identifier, which enables other ranging capable devices that are part of the ranging constellation, are in the vicinity of the ranging constellation, and / or are capable of ranging and / or location services to access location and / or ranging services via a sidelink connection based on the specific relay service code or service identifier. This allows the use of sidelink resources to improve ranging and / or location services.

[0029] It should be noted that the above apparatus may be implemented based on a separate hardware circuit involving an arrangement of separate hardware components, integrated chips, or chip modules, or based on a signal processing device or chip controlled by a software routine or program stored in a memory, written to a computer readable medium, or downloaded from a network such as the Internet.

[0030] It is to be understood that the apparatus according to claim 1, the mobile communication device or access device according to claim 15, the system according to claim 17, the method according to claim 21 and the computer program product according to claim 22 have similar and / or identical preferred embodiments, in particular as defined in the dependent claims.

[0031] It shall be understood that a preferred embodiment of the invention may also be any combination of the dependent claims or the above embodiments with the respective independent claim.

[0032] These and other aspects of the invention will be apparent from and elucidated with reference to the embodiments described hereinafter. [Brief description of the drawings]

[0033] [Figure 1] 1A-1D are schematic diagrams illustrating different concepts of providing ranging services to mobile devices with or without network coverage. [Diagram 2] FIG. 2 is a schematic diagram showing different directions in a spherical coordinate system. [Diagram 3] FIG. 2 is a schematic diagram showing the timing of data transmission between a transmitter and a receiver to explain the concept of round trip time. [Figure 4] FIG. 1 is a schematic diagram of the concept of angle of arrival based on phase difference considerations. [Diagram 5] 1 is a schematic block diagram of a wireless system for providing ranging and / or positioning services in accordance with various embodiments. [Figure 6] 1 is a schematic diagram of a network architecture in which a mobile terminal approaches a constellation of mobile terminals and receives assistance with location coordinate ranging services, according to various embodiments. [Figure 7] 1 is a schematic diagram of signaling and processing for a ranging-based positioning service according to various embodiments. [Figure 8] FIG. 1 is a schematic diagram of an example conceptual architecture of an anchor UE supporting a subset of LMF functions as a proxy. [Figure 9] 1 is a schematic diagram of signaling and processing for a ranging-based positioning service according to various embodiments. [Figure 10] 1 is a schematic diagram of signaling and processing for a ranging-based positioning service according to various embodiments. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0034] Next, embodiments of the present invention will be described based on ranging and / or positioning (sometimes called "localization") services of cellular networks, where, for example, 4G network elements are incorporated into the proposed 5G solution. Furthermore, at least some of the following embodiments will be described based on 5G New Radio (5G NR) radio access technology.

[0035] 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). Furthermore, the abbreviations "eNB" (4G terminology) and "gNB" (5G terminology) refer to access devices such as cellular base stations or WiFi access points. The eNB / gNB is a part of the RAN that provides an interface to functions in the CN. The RAN is a part of the wireless communication network. The RAN implements a radio access technology (RAT). Conceptually, the RAN exists between communication devices such as mobile phones, computers, or any remotely controlled machine, and provides their connection with the CN. The CN is the core part of the communication network, providing a number of services to customers interconnected through the RAN. More specifically, the CN directs communication streams over the communication network and possibly other networks. 3GPP® specifications 23.303, 23.304, 24.334, and 24.554 for 4G and 5G networks, respectively, define, among other things, so-called Proximity Services (ProSe) features that enable connectivity of cellular communication devices (e.g., UEs) that are temporarily not in the coverage of an access device (eNB). One particular feature is called ProSe UE-to-network relaying, or relaying UE. A relaying 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 between the OoC UE and the eNB in ​​both directions. The local communication between a relaying UE and an OoC-UE is called D2D communication, sidelink communication, or PC5 communication. The abbreviation "PC5" refers to the interface for sidelink communication defined in 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).

[0036] 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 with the CN as opposed to a direct network connection, which is the usual case (see 3GPP specification TS22.261 v16.10.0).

[0037] Furthermore, 3GPP® specifications TR23.733 v15.1.0 and TR36.746 v15.1.1 provide research on architecture enhancements to enable IoT devices (in the role of remote UEs) to operate at very low power, for example by using relay UEs to connect to a wider network. Relay UEs are physically very close, so that very low power transmissions can be used to reach relay UEs. This work also includes improvements to security, speed, and stability of ProSe. These extensions of ProSe are called enhanced ProSe ("eProSe").

[0038] ProSe can also be used for direct communication between two UEs. Further radio level details regarding ProSe, V2X and sidelink communications are described in 3GPP specifications TR37.985, TS38.300 and TR38.836.

[0039] Ranging can be defined as the process of measuring the distance and / or the relative direction angle between two wireless devices in a three-dimensional space. In the first mentioned specification TR22.855 "Study on Ranging-based Services", a ranging-based service is defined as an application that exploits 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. Next to the distance and direction angle measurements, a relevant measurement is whether two wireless devices are in direct line of sight or not, since this measurement is relevant for many use cases where it is assumed that the UEs interact with each other when they are in line of sight, e.g. when they are in the same room.

[0040] The term "ranging reference signal" is used herein to refer to a signal used to determine the distance and / or angle between two devices that are connected through a device-to-device connection (e.g., using sidelink and / or PC5) rather than an infrastructure connection (e.g., using the Uu interface). A ranging reference signal is a position reference signal and / or a sounding reference signal or other signal used to determine the distance and / or angle between devices (e.g., signals used for round trip time (RTT) measurements) possibly using resources (configured or allowed by the access device) for device-to-device (e.g., sidelink) communication / discovery and / or resources specifically reserved for transmitting reference signals or other signals used to determine the distance and / or angle between the devices.

[0041] The terms "ranging capable device" and "ranging capable UE" are used herein 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 does not need to be enabled all the time, but is enabled / triggered on demand (e.g., by request from another device or network function). Also, the components, subsystems, and / or functions are not always approved to be used to perform distance measurements. Thus, the terms "ranging capable device" and "ranging capable UE" may also be interpreted as capable and authorized / enabled to perform distance and / or angle measurements between itself and another device. Also, in a sentence where the word "capable" is used, the term may be interpreted / restricted to be enabled and / or authorized.

[0042] Ranging capabilities vary from device to device. For example, not all devices can calculate angles because angle calculation requires multiple antennas. The device's ranging capabilities (which may be interchangeable as part of the discovery process) can be used to determine what the device can do and what measurements can be performed. Note that angle calculation may need to be an explicit capability, not just based on the ability to declare the number of antennas. Just having one or more antennas does not automatically mean that the device can calculate angles. Angle calculation also requires sensors (e.g., magnetometers, gyroscopes, accelerometers) that derive the orientation and / or angle relative to a reference point such as magnetic north, and an angle / orientation calibration mechanism. Angle also represents the difference in altitude, using a reference altitude (e.g., meters above sea level and / or air pressure, floor information, terrain altitude data of the device location) and an altitude calibration mechanism.

[0043] Distance / angle / position calculation techniques 1A-1C illustrate schematic diagrams of 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 ellipse shows a perspective view of a circular coverage area around an access device (e.g., gNB) for accessing a 5G cellular network. In FIG. 1A, a first UE 10 is located within the coverage area of ​​the access device 20, and a second UE 12 is located outside the coverage area and thus 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 a set of UEs (e.g., observer UE (O-UE) and target UE (T-UE)) can be visualized on a three-dimensional (3D) sphere in a two-dimensional (2D) plane as shown in Figure 2. The horizontal direction of the target UE (i.e., azimuth angle (Az)) is the angle formed 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 origin of the observer UE to the target UE.

[0048] For example, as described 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 yields two parameters: the distance in meters between the two UEs and the angle in degrees as the target UE rises 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 in the sub-nanosecond range) with an effective ranging distance of 20 m, and a maximum tolerance of ±2° in horizontal and vertical planes in a coverage range of -45° to +45° Angle of Arrival (AoA) with respect 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 distance and angle from the ranging service are converted to location coordinates. The UEs involved in ranging are expected to move with different speeds (e.g., 1 m / s to 10 m / s), and multiple simultaneous ranging operations are performed between multiple UEs in a given area, and the UE can perform multiple simultaneous ranging operations with other UEs present in the area.

[0050] So-called "peer-to-peer ranging" can be implemented in a variety of ways, including but not limited to the following ways. i. Two-way ranging. It is a process where two devices A and B communicate data packets and acknowledgement packets back and forth to each other. This technique takes into account the time delay caused by natural radio signal propagation and processing delays at device B (i.e., the time it takes device B to retransmit a packet to device A). Then, device A calculates the one-way flight time as half the difference between a) the time it takes device A to send 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. Device B includes information in its response packet so that A can calculate the time it takes for B. Then, device A uses the one-way flight time to calculate the distance between the two devices A and B. Device B performs the same procedure as device A so that B can also calculate this distance. In this technique, the processing delays are taken into account in two successive packet transmissions, and the distance is calculated simultaneously at both devices, so there is no need to synchronize the clocks of the two devices with each other. ii. One-way Ranging. It is a process in which at least one packet is sent between a sending wireless device A and a receiving wireless device B. The devices are synchronized with each other by a common clock source. The time of flight is then measured as the difference between the receive time at device B and the transmit time at device A. Device A includes a timestamp of its transmit time in the data packet so that device B can calculate this time difference. The accuracy of the ranging depends on the accuracy of the clock synchronization achievable between the two devices.

[0051] Peer-to-peer ranging operations depend on several 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 wireless radio. These parameters are also important for general wireless communication, and as a result, there are many standardized techniques to achieve the highest communication performance for a given radio. For example, in 3GPP, the sidelink radio resource protocol described in specification 36.331 v16.4.1 ensures high accuracy clock time synchronization between two sidelink UEs operating in multiple in-coverage and out-of-coverage scenarios.

[0052] Positioning may be defined as the process of determining the location coordinates of wireless devices, such as but not limited to mobile phones, wearables, and IoT devices, according to a location coordinate system. Once the location coordinates of the device are determined, the location coordinates may be placed on a map using a mapping function. Positioning is usually distinguished into absolute positioning (i.e., determining the geographic coordinates (location coordinates) according to a standardized geographic coordinate system) or relative positioning (i.e., specifying the coordinates and / or angles and distances relative to a reference point (e.g., using a local coordinate system). Some examples of how absolute or relative positions may be expressed can be found in 3GPP specification TS 23.032. A typical example is a satellite-based location service (e.g., Global Positioning System (GPS) or Global Navigation Satellite System (GNSS)), in which the location coordinates of a 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, where the satellites act as a clock synchronization source 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. There are also several indoor positioning techniques available based on radio frequency technologies such as Bluetooth, UltraWideBand (UWB), or Wi-Fi that can locate / determine the coordinates of tags emitting radio frequency (RF) in indoor environments. The locations of these tags are then mapped onto the indoor floor plan using indoor coordinates estimated based on RF propagation characteristics such as time delay, multipath reflections, received signal strength, etc. measured using RF communication between tags and anchor nodes placed at known locations in the building.

[0053] The positioning techniques used to obtain the coordinates of the device's current location can be accomplished in a number of ways, but typically include 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 may be determined using a variety of techniques including round trip time (RTT), time of flight (ToF), time difference of arrival (TDoA), angle of arrival / angle of departure (AoA / AoD), and / or a combination of each.

[0054] Round Trip Time (RTT) defines the duration from when a data packet is transmitted by a transmitter (Tx, e.g., an access point / device) to when the same data packet is received and acknowledged by a receiver (Rx, e.g., a mobile phone / device), i.e., the time duration until the transmitter receives the acknowledgement. Since data packets travel at the speed of light (approximately 3.3ns / m) in the air medium, the duration of the data packet traveling in the air is proportional to the actual distance between Tx and Rx. In a scenario where the internal clocks of Tx and Rx are not synchronized, one-way time measurement cannot be made based on the difference between the transmit timestamp and the receive timestamp, since the timestamp also contains timing errors caused by, among other things, the internal clock drift and the uncertain clock offset between Tx and Rx. Since the internal clocks of Tx and Rx are not synchronized, the difference in the timestamp 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).

[0055] FIG. 3 shows a schematic timing diagram of data transmission between a transmitter and a receiver to explain the concept of round trip time.

[0056] In the timing diagram of FIG. 3, time progresses from top to bottom and the flow of information between a transmitter (Tx) and a receiver (Rx) is indicated by respective arrows.

[0057] According to Fig. 3, a data packet (DP) is transmitted from Tx to Rx at time t1 and is received by Rx at time t2. An acknowledgement (ACK) is transmitted from Rx to Tx at time t3 and is received by Tx at time t4.

[0058] The round trip time (RTT) can be obtained by simple addition and subtraction of the four timestamps t1 to t4, without needing to know the clock offset, as follows: RTT = (t4-t1+t2-t3) where t1 is the transmission time, t2 is the reception time, t3 is the acknowledgement transmission time, and t4 is the acknowledgement reception time.

[0059] 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. Also note that RTT measurement based distance estimation does not require synchronization between the transmitter and receiver. The single distance calculation can be extended to two- and three-dimensional space for multiple distance estimation and then converted to estimates of location coordinates (both local and global) when the coordinates of each transmitter are known a priori. Some 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.

[0060] The 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 in this method, only the forward path (i.e., from Tx to Rx) is considered, 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 assumed to be correct and, among other things, the timing errors caused by the internal clock drift and the uncertain clock offset between Tx and Rx are corrected. Assuming that Tx and Rx in FIG. 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 communicated later) and its own measured timestamp t2. The time of flight can also be calculated by Tx knowing the timestamp t2 (e.g., communicated later by Rx to Tx) and its own measured timestamp t1. The single distance calculation can be extended to two- and three-dimensional space for multiple distance estimations, and then converted to estimates of location coordinates (both local and global) when the coordinates of multiple reference devices (acting as either transmitters or receivers) are known a priori.

[0061] The time of arrival difference corresponds to the difference in time stamps when a data packet is received by several clock-synchronized receivers (Rx, e.g., access points / devices that are synchronous location reference stations), which indicates that the data packet was transmitted by an asynchronous transmitter (Tx, e.g., a mobile phone / device or an asynchronous location tag whose location coordinates are determined). Note that the roles can be reversed, e.g., a mobile phone / device can be an asynchronous Rx and an access point / device can be a synchronous transmitter. Note that one transmission of a data packet by a transmitter is received simultaneously by several synchronous receivers located within the coverage area of ​​the transmitter. It is important that the receivers are clock-synchronized and that their location coordinates are known to the central location server, but the transmitter whose location coordinates are determined is not synchronized with other transmitters or receivers. The central location server can receive the time of arrival of the data packet from each receiver i=0...N and 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 and Δt ij is the difference in arrival time between receiver i and receiver j, and d i is the unknown Tx-to-Rx distance for receiver i, and Δd ijis the difference in Tx-to-Rx distance between receiver i and receiver j. This calculation is applicable to 2D and 3D space for distance difference estimation and can be converted to location coordinates (both local and global) if the receiver coordinates are known a priori. Note that the transmitter cannot calculate its own location locally on the device, only the location server can calculate the transmitter location using the localization infrastructure and the network of synchronized receiver nodes. Note that the location server is located at one of the clock-synchronized receivers. The transmitter location can be communicated over another communication channel (e.g., to the application, the transmitter, or one or more receivers) or can be fixed in one of the responses from the receiver to the transmitter on the same channel used for transmitting the data packet.

[0062] Alternatively or additionally, the receiver transmits receiver measurements (e.g., time of arrival information) rather than calculated distance and / or angle to a transmitter or location server, which calculates the resulting distance 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 and 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).

[0063] In addition to time-based distance estimates, the angle of arrival can be derived from phase information of the RF signal received at the receiver using an antenna array and 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.

[0064] FIG. 4 shows a schematic diagram of the concept of angle of arrival based on phase difference consideration.

[0065] In the example of Figure 4, the angle of arrival of the incoming RF signal (indicated by the two diagonal arrows) can be calculated as follows: In principle, a receiver with two antennas φ1, φ2 with different receive phases separated by a distance d can determine the phase difference Δφ of the received signals at the receiver and use it to estimate the angle of arrival according to the following equation: Δφ=[φ1-φ2]=2π[(dcosθ1) / λ]+2kπ where θ1 is the estimated angle of arrival, k is the wavenumber which can be calculated by k=2πλ, λ is the wavelength of the RF signal which can be calculated by λ=c / f, c is the speed of light, and f is the radio frequency of the signal.

[0066] The angle of arrival of the RF signal at the receiver can be estimated using a simple approach based on the measured phase difference using the following equation: cosθ1=[(Δφ / 2π)-k]*[λ / d]

[0067] In addition to the above techniques, it should be noted that there are several well-known techniques 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 (see J. Capon, "High-resolution frequency-wavenumber spectrum analysis", IEEE Proceedings, Vol. 57, No. 8), and Signal and Noise Subspace Estimation. Other complex estimations of AoA use three or more antennas at the receiver, which allows obtaining both angle and distance measurements based on RF signals transmitted by asynchronous transmitters with somewhat simpler hardware and a single antenna, with only one receiver instead of three synchronous receivers. Similarly, if the transmitter uses multiple antennas, the radiation angle (of the signal at the transmitter) can be determined and used for ranging / location estimation.

[0068] The process of obtaining location coordinates of a device and locating the device on a map using mapping functionality is also provided by Location Services (LCS) provided in the 3GPP® system, where 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 methodologies as described, for example, in 3GPP® specifications TS 23.271 “Functional stage 2 description of Location Services (LCS)” for 4G, Rel-16, and 3GPP® specifications TS 23.273 “5G System (5GS) Location Services (LCS); Stage 2” for 5G, Rel-17.

[0069] A typical difference between location services and ranging services provided by 3GPP systems is that location services measure the geographic coordinates of a device within a cell coverage area (e.g., 1-5 km) and provide good accuracy in outdoor environments where line of sight (LOS) with a base station is possible, and communication paths can be properly modeled and taken into account using channel models for urban and rural environments, whereas ranging services measure the distance and / or angle between two devices within a short distance (e.g., 20 m) and provide good accuracy in outdoor and especially indoor environments where two ranging devices may be within line of sight (LOS) of each other.

[0070] Combining location and ranging service functionality provides location services with, for example, improved accuracy and better indoor position estimation. The location service, ranging service, or a combination thereof, verifies the integrity / measures accuracy / determines errors and possibly corrects the measured distance, angle, location information (e.g., coordinates), etc., provides the distance, angle, location information to the UE, core network functions, applications, or other location / ranging services, stores the distance, angle, location information in non-volatile storage, and / or may combine the distance, angle, location information with distance, angle, location information from other sources or from various location / ranging mechanisms. In this disclosure, some terms are taken from TS 23.273. These terms, such as "location service", "location request", "location information", "location / location result", etc., may be equivalently replaced with "ranging / sidelink positioning service", "ranging / sidelink positioning request", "ranging / sidelink positioning information", "ranging / sidelink positioning result", etc.

[0071] It should be noted that a location service may also provide a ranging service (and vice versa). For example, if the location of two devices can be observed / determined, such as through GNSS, the distance and / or angle between the two devices may be calculated and exposed as part of a ranging service that allows a device to request the distance and / or angle between itself and another device. In such cases, the two devices may still be requested to perform ranging measurements between each other to improve the accuracy of the distance and / or angle between the two devices or to determine deviations to the observed / determined locations.

[0072] The distance to coordinate conversion may be achieved, 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 the orientation of device A relative to a coordinate system is known, device A can obtain the coordinates of device B using the distance and angle measurements between device A and device B.

[0073] For example, for geographic coordinates expressed in radians, the latitude (lat1) and longitude (lon1) of device A are assumed to be known. Then, using a spherical Earth model, the geographic coordinates (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.

[0074] As another example, for a local 2D Cartesian coordinate system used for an area, the X and Y coordinates (x1 and y1, respectively) of device A are assumed to be known. The X / Y location coordinates (x2 and y2, respectively) of device B can then be calculated using the following formula: x2=d*cos(alpha)+x1 y2=d*sin(alpha)+y1 Here, all coordinates and distances d are expressed in meters and angles (alpha) measured with respect to device B by A.

[0075] Alternatively, the conversion from distance to coordinates of the coordinate system is done using other concepts such as inverse haversine rule, degree length, Molodensky method, block shift method, etc., depending on the accuracy required and the type of coordinate system used by the application. Current ranging and position estimation techniques can be improved in the following areas: i. Location accuracy is highly dependent on signal path losses and decreases with decreasing signal quality in indoor and deep indoor environments where cellular coverage is very poor. Furthermore, location service accuracy decreases in remote outdoor environments where the number of base stations is limited, resulting in sparse or no signal coverage. In such areas, depending on the positioning method used, trilateration or triangulation of a mobile device (e.g., UE) requires a longer initial latch time to ensure that at least three different signals from at least three different base stations can be received simultaneously. When a mobile device is moving in such poor coverage areas, the continuity and reliability of the location services provided by the base stations are significantly impaired, making the service unusable for real-time location tracking. ii. The accuracy of ranging in outdoor environments depends heavily on the channel variability and reflective properties of objects surrounding the device performing the ranging operation. In indoor environments, the user of the mobile device (e.g., UE) can fairly control the environment with respect to objects and surrounding environment before ranging between two devices, but in outdoor environments, the control of the environment is uncertain and often adversely affects the accuracy of ranging. In addition, the movement of the mobile device in outdoor environments also has a significant impact on the accuracy of ranging due to the possible Doppler effect in the RF propagation channel. Therefore, ranging measurements between two devices in outdoor environments become unusable due to the significant degradation in the RF channel.

[0076] Below, embodiments are described in which ranging and / or positioning concepts are complemented by the use of ranging measurements (e.g., distance, angle, and altitude) between a transmitter and a receiver, thereby improving positioning accuracy and reducing power consumption associated with these concepts.

[0077] Some use cases require a conversion from ranging measurements to location coordinates, which allows UEs that do not have positioning services or additional positioning modules available to obtain location coordinates derived from ranging information. In addition, devices with very low positioning accuracy, especially in indoor environments, benefit from ranging, thereby improving positioning accuracy in indoor and / or out-of-coverage environments from hundreds of meters to less than a meter. Furthermore, accurate positioning and continuous tracking of low-power IoT devices is a requirement for yet another use case, which allows adaptive provision of Quality of Service (QoS), e.g., depending on the location, a high bandwidth is provided to a mobile UE at location X and only a low bandwidth is provided to a mobile UE at location Y. Some of the identified preferred use cases require forming clusters of UEs based on location information in order to provide location-based QoS to groups of UEs.

[0078] It is important to note that throughout this disclosure, wherever the concept of ranging and / or positioning is mentioned, any or a combination of the ranging and / or positioning methods listed above, or other ranging or positioning methods known to those skilled in the art, may be used.

[0079] Ranging constellations (including their configuration) FIG. 5 illustrates generally a block diagram of a wireless system for providing ranging and / or positioning services, according to various embodiments.

[0080] 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 adapted / prepared for one or more device UEs 10 to join the group. The device UEs 10 join the ranging constellation 50, for example, to initiate a ranging procedure or to participate in ranging of other UEs by acting as additional anchor UEs 14. A single distance and / or angle obtained from a ranging procedure is not sufficient to determine the (absolute or relative) location of a UE. In one example, the ranging constellation 50 has at least two or more anchor UEs 14 to determine the position of the device UE 10 by determining the distance and / or angle between the device UE 10 and the anchor UE 14 of the ranging constellation, and to use the determined distance and / or angle to calculate the location using trilateration and / or triangulation. If additional information such as specific coordinates, whether the devices involved in the ranging are at the same height (e.g., a certain number of meters above sea level, on the same floor) or on the same reference plane is known or can be determined in advance, ranging between the device UE 10 and a single anchor UE 10 in the constellation is sufficient to determine its relative or absolute location.

[0081] The devices that make up the ranging constellation 50 are selected based on a set of one or more selection criteria for candidate devices, such as the device's support for GPS / GNSS, whether the device's location is known, the device's particular ranging capabilities, existing membership in other ranging constellations, the device's distance to a particular reference point (e.g., a nearby access device), the device's speed, and / or a determination of whether the device is fixed or mobile or whether such candidate device is within sidelink discovery range of another device (e.g., an anchor device). The formation of a 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.

[0082] A device UE 10 is added to or removed from an existing ranging constellation. Similarly, an anchor UE 14 is added to or removed from an existing ranging constellation. The ranging constellation 50 is given an identification (e.g., by a management entity, etc.) and this identification is transmitted to each device participating / constituting the ranging constellation 50. The identification is also used during discovery of ranging capable devices, during connection setup between ranging capable devices, and / or during message exchange to initiate a ranging session. A ranging constellation is assigned multiple identities (e.g., both a unique constellation instance identifier and a constellation type identifier).

[0083] It should be noted that the addition, removal and joining of the device UE 10 to the ranging constellation does not mean that the device UE 10 needs to have information about all anchor UEs of the ranging constellation or needs to establish sessions with all anchor UEs of the ranging constellation. For example, the set of other UEs of the ranging constellation is only known by the LMF or other management entity. The UEs of the ranging constellation form a trusted group / domain, whereby UEs that are part of the ranging constellation share the same / similar group / domain credential or authorization token and (if necessary) through this information, the UEs can prove to other UEs of the ranging constellation that they are part of the same ranging constellation if they 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 is used to protect (e.g., encryption and / or integrity protection) message exchanges between UEs that are part of the ranging constellation. This includes protection of multicast / groupcast messages. A UE that does not possess 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 or participating in the constellation. Alternatively or additionally, a UE in a ranging constellation is provided with individual credentials for each other UE in the ranging constellation.

[0084] The device UE 10 corresponds to a wireless device requiring ranging and / or positioning services and is also referred to as a target UE. It should be noted that in the description of this and the following embodiments, the terms "device UE" and "UE" are used interchangeably and are intended to mean the same device. Also, the terms position and location are used interchangeably and can be relative (e.g., coordinates of a reference plane) and absolute (e.g., geographic coordinates).

[0085] 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 provides ranging / positioning services to the UE and other anchor UEs.

[0086] It should be noted that device UE 10 and anchor UE 14 can be mobile phones or any type of connected device and can support Uu and PC5 3GPP® interfaces. These devices can support multiple radio access technologies, including but not limited to 2G / 3G / 4G / 5G networks as described in 3GPP®, Wi-Fi® spectrum, Bluetooth® spectrum, and non-3GPP® wireless technologies operating in unlicensed wireless spectrum such as ISM bands. The mobility of device UE 10 and anchor UE 14 does not affect the ability of device UE 10 to become anchor UE 14 or vice versa. Depending on the application, anchor UE 14 can also be a fixed device (e.g., a smart TV) and mobile device UE 10 (e.g., a mobile phone) is authorized to become anchor UE 14 when moving or when it is fixed and remains in one place. Typically, the anchor UE 14 should be aware of its own location, be able to obtain its own location from a location service, or be able to use a ranging procedure with the device UE 10 to provide / determine a reference plane and reference direction for distance / angle measurements, and be able to do so even when it is out of the coverage of the network. The location of the anchor UE should be relatively stable, e.g. not moving or shaking excessively, or at least stable compared to the device UE 10 (e.g., when both are moving in the same direction, e.g. both UEs are in the same vehicle, the relative speed is more important than the absolute speed of the ranging UE 14). The anchor UE is preferably in the coverage of the network so that it can access the location services provided by the core network, obtain its location, maintain synchronization with the network, and obtain approval for the ranging procedure.

[0087] Both the device UE 10 and the anchor UE 14 have receiver units capable of receiving ranging reference signals and / or other wireless signals used for distance / angle measurements and determining the timing of these signals, and 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 unit (or another computation unit of the device UE 10 or the anchor UE 14) can also calculate distance, angle or (relative) position based on these distance / angle / positioning measurements (possibly augmented with data from other sensors such as air pressure sensors) and / or distance / angle / positioning measurements received from other devices (possibly augmented with data from other sensors such as magnetic sensors). Additionally, the device UE 10 and the anchor UE 14 have transmitter units capable of transmitting signals used for distance / angle measurements (e.g., position reference signals or sounding reference signals) and determining the timing of these signals. The anchor UE has a known / fixed location and is therefore a position reference unit as described in 3GPP® document R2-2109489, and additionally transmits this information to the device UE 10 and / or other anchor UEs 14. Device UE 10 and anchor UE 14 support the transmission of signals and reception of signals enabling communication with wireless access devices (e.g., as defined in 3GPP® specification TS 38.300) and are capable of communicating with the (cellular) core network and its services (e.g., as defined in 3GPP® specification TS 23.501), such as location services (e.g., as defined in 3GPP® specification TS 23.273), using protocols such as the LTE Positioning Protocol (LPP) defined in 3GPP® specification TS 36.355 or the NR Positioning Protocol A (NRPPa) defined in 3GPP® specification TS 38.455.Additionally, device UE 10 and anchor UE 14 support discovery and communication with other device UEs and / or anchor UEs over PC5 / sidelink (eg, as defined in 3GPP specifications TS38.300, TS23.287, TS23.304, and TR37.985).

[0088] The device UE 10 , the anchor UE 14 and the wireless access device 20 together form a positioning constellation (PC) 60 .

[0089] Depending on the application and accuracy needs, ranging or sidelink based positioning is performed between the device UE 10 and one or more anchor UEs 14. For example, simple applications such as coarse ranging may be used with a single anchor UE 14 to provide a rough range / area indication. Other applications require three or more anchor UEs 14 tightly clock synchronized with the device UE 10.

[0090] 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 provisioning relative positioning services (e.g., determining location in a reference coordinate system). In the ranging constellation 50, one of the anchor UEs 14 is a head anchor UE or lead anchor UE that is responsible for managing the set of remaining anchor UEs 14 (e.g., acts as a synchronization source for the other anchor UEs). Additionally, the anchor UE is configured to support a management entity, e.g., select, configure, reconfigure, etc. the other anchor UEs 14.

[0091] At least one wireless access device 20 (e.g., a base station or a gNB) is configured to handle the connectivity of the UE to the core network (CN) 30. The wireless access devices 20 also support several positioning techniques, alone or in combination with other wireless access devices 20. The wireless access devices 20 are responsible, among other things, for radio resource allocation and scheduling, clock time synchronization, and power control of connected devices.

[0092] The wireless access device 20 also provides positioning signals and (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 conjunction with a positioning service in a core network such as the 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, and 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 location and may have received a location from a management entity (e.g., an installer UE). Later, when the anchor UE is not in coverage, it can still transmit ranging signals and / or information about its location even when it is not connected to the wireless access device 20.

[0093] Furthermore, the core network (CN) 30 provides networking functions to control the access network and manage the UE devices 10 and anchor UEs 14 that subscribe to and are served by the access network. The core network (CN) 30 is, for example, a 5G core network. The core network 30 may include several 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 publication function (NEF) 38 that enables application functions (AFs) 40 to connect to the core network 30.

[0094] It should be noted that the network controller device plays the role of the core network 30 in the described embodiment. It should also be noted that the LMF 34 or RMF 36 includes or is connected to a set of services / functions (e.g., a Gateway Mobile Location Center (GMLC)) responsible / capable of determining, verifying, providing, and / or storing a set of location, distance, angle, coordinates, and other related information for location and / or ranging services, managing, configuring, operating a set of location and / or ranging services, and / or combining distance, angle, location information with distance, angle, location information obtained from other sources or from various location / ranging mechanisms. The term LMF or RMF refers to such services / functions or combinations thereof. The LMF and RMF can also be considered as location services, ranging services, or combined location and ranging services. The application functions 40 are third party applications involved in leveraging the services provided by the core network 30 and the wireless connectivity provided to the UE 10 and / or anchor UE 14.

[0095] According to various embodiments, a management entity is provided that configures one or more UEs as anchor UEs 14 to form a ranging constellation 50 to support ranging services, location services, and / or ranging-based positioning services (i.e., a combination of ranging and location service functionality). In addition to improving localization and ranging accuracy, the ranging constellation 50 also helps to reduce power consumption of at least the involved UEs 10 by combining ranging and location services.

[0096] More specifically, simple ranging measurements between devices can be locally or centrally initiated and / or coordinated to improve location accuracy. In examples, this can be accomplished by using ProSe discovery messages, carrier phase based ranging / positioning techniques, and / or ranging / positioning signals transmitted over 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).

[0097] The core network 30 (e.g., a network controller device) together with the wireless access devices 20 (e.g., base stations or gNBs) supports ranging and / or positioning services required by one or more devices UE 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 through which a user can select and (re)configure a set of UEs to form a ranging constellation and / or manage ranging and / or location procedures and / or ranging and / or location services, including configuring requirements and parameters of ranging and / or location procedures / services, including but not limited to the following: The ranging / positioning method to be used (e.g. RTT-based, TDOA-based, AoA / AoD-based) The radio access technology used (e.g. 3GPP® LTE, 3GPP® 5G NR, Wi-Fi®, Bluetooth®, UWB, …) - Bands to be used (including whether to use unlicensed / licensed spectrum) Bandwidth used Minimum / maximum / default measurement duration and / or ranging reference signal / timing of measurements -Min / Max / Default transmit power to use Desired / minimum accuracy of ranging Constellation size (e.g. number of devices, identity of devices involved, area information, maximum distance) Constellation configuration (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) -Sampling frequency for distance and position measurement Credentials to use during discovery and / or ranging procedures (e.g. security keys, identification information) - providing an intermediate / proxy configuration function, through which a network entity (e.g. location / ranging management function), an access device (e.g. base station), or an application function (e.g. by a network publishing function) can select and (re)configure a set of UEs to form a ranging constellation and / or remotely manage ranging and / or location procedures and / or ranging and / or location services (e.g. configuring requirements and parameters of ranging and / or location procedures / services as explained in the previous item). The configuration by the network entity can be done 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 decide, e.g. how to determine / select anchor UEs or how to configure 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 transmit it to a ranging 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 discovered by UEs of a ranging constellation (identities of discovered devices, discovered 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. The management entities are: A function provided by the UE (e.g., anchor UE 14 or installer UE) through which a user can manually manage the ranging constellations, ranging and / or location procedures, and / or ranging / location services, and / or a network entity (e.g., a location service to which the anchor UE is communicatively coupled) can remotely manage the ranging constellations, ranging and / or location procedures, and / or ranging / location services (e.g., configuring the requirements and parameters of the ranging and / or location procedures / services, as described above). A user or application communicatively coupled to the core network 30 (e.g., a network controller device), for example via the network publishing function 38, the location management function 34, the ranging management function 36, and / or other core network functions, through which the ranging constellations and / or the ranging and / or location procedures / services may be managed (such as configuring the requirements and parameters of the ranging and / or location procedures / services, as described above). A selected one of the wireless access devices 20 and / or core networks 30 (e.g. a network controller device or a visited core network) that may (automatically) manage the ranging constellations, the ranging and / or location procedures of the set of connected UEs, and / or the ranging and location services that it provides to the set of connected UEs or that, after being configured by, for example, a Location Management Function 34 and / or a Ranging Management Function 36 (operated by, for example, the home core network), are provided to the set of connected UEs. A Location Management Function 34 and / or Ranging Management Function 36, either inside or outside the core network 30, which possibly cooperates with core network functions such as Network Data and Analysis Function (NWDAF, e.g. determining device density, how many devices are typically registered at a particular time period, etc.), User Data Management (UDM, e.g. for subscription related data), and / or Policy Control Function (PCF, e.g. for policy related data) to manage ranging and / or location procedures / services (e.g. configuring requirements and parameters of ranging and / or location procedures / services and / or configuring ranging constellations) based on operator managed default operational settings, policies, location databases, historical measurement data, artificial intelligence models.

[0098] The location management function 34 and / or ranging management function 36 or other management entity configures the one or more devices UE 10, the one or more anchor UE 14, and / or the wireless access device 20 (management entities) based on the requirements and parameters of the ranging and / or location services (e.g. provided through the network publication function). The configuration is done by sending secure messages to the respective device UE 10, 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 by one of the involved devices. For this purpose, the device UE 10 and / or anchor UE 14 needs to support a protocol for configuration of ranging procedures / services (e.g. an extension of the LTE Positioning Protocol (LPP) defined in the 3GPP specification TS 36.355). If one or more of the UEs in the ranging constellation are out of coverage or are not directly connected to or managed by the ranging / location management function, the configuration is provided or forwarded to these UEs by the in-coverage UEs (i.e. in the case of partial coverage situations where at least one of the UEs in the ranging constellation is in coverage) or by a management entity (e.g. supported by a (head) anchor UE and operating out of coverage).

[0099] In one example, the LMF is used to configure ranging-capable UEs that receive static and / or dynamic configuration information. For aspects of the configuration that are unlikely to change from procedure to procedure or even during a procedure, i.e., static configuration aspects such as the default coordinate system to use or other default values ​​to obtain when the device goes out of coverage and / or dynamic configuration is not available, or the conditions for when to perform a particular role (e.g., whether the device's location is stable) or policies that determine which device identities and / or security credentials to use during discovery and / or ranging procedures, provisioning is also performed by other core network functions such as the PCF or DDNMF.

[0100] The dynamically configurable parameters of a ranging capable UE that should be considered are: - The ranging / positioning method used (e.g. RTT, TDOA, …) -Frequency band and bandwidth used -Sampling frequency for distance and positioning measurements Ranging and location signals and timing / duration / of measurements -Min / Max transmit power to use Device role (e.g. anchor UE, target UE) Ranging "constellation" information or ranging session related information (e.g., identity of anchor UE that cooperates to provide ranging / sidelink location services (e.g., L2 identity, User Information ID, or PRUK ID), known location of anchor UE, constellation identifier) Coordinate system to be used A device, location / ranging service, or location / ranging service proxy that collects measurements to calculate distance, angle, or position The dynamic parameters mentioned above are changed for each ranging session / procedure or even during the procedure. The parameters are changed and / or configured per tracking area, per cell, per registration area or per network (e.g. Visiting-PLMN vs. Home-PLMN). These dynamic parameters are exchanged as part of a negotiation procedure between the device UE 10 and one or more anchor UEs 14 (e.g. during discovery, capability exchange or during connection setup over sidelink or during initiation of a ranging session / procedure), whereby one UE informs the other UE about a recommended value or a set of possible values ​​(e.g. based on its capabilities) of one or more of these configurable parameters, after which the other UE (usually one of the anchor UEs, the head anchor UE, with or without cooperation / requesting LMF and possibly taking into account the one UE's will and / or capabilities) decides which values ​​to use for the configurable parameters and sends a message containing the selected values ​​to the one UE. This is done for example by extending the direct communication request and the associated direct communication response messages with additional fields for this purpose. Also, for some configuration parameters that are changed during a ranging session / procedure, such as the device role, the changes to one or more of the configuration parameters are provided through a message exchange with the other UE (e.g., by extending additional fields in the direct link modification request / accept message), at which point the session / procedure is adjusted or aborted and / or a new negotiation procedure is initiated. Similarly, when the device UE 10 or anchor UE 14 participates in a negotiation procedure with the LMF (e.g., during capability exchange or connection setup with the LMF), this causes the UE to inform the LMF of the recommended and / or possible values ​​of one or more of these configurable parameters, which then determines which values ​​to use for the configurable parameters and sends a message containing the selected values ​​to the UE. The LMF also provides these configurable parameters as part of a location request to the device UE 10 or anchor UE 14.Additionally or alternatively, the device UE 10 or anchor UE 14 does not directly provide the list of capabilities or the recommended values ​​of configuration parameters to the other UE or LMF, but instead is provided with an identifier by means of which the other UE or LMF can obtain the list of capabilities and / or the recommended values ​​of configuration parameters of the device UE 10 or anchor UE 14 by message exchange with a core network function or database storing the list of capabilities and / or the recommended values ​​of configuration parameters of rangeable UEs linked to one or more identifiers of the rangeable UEs. The identifier of the device UE 10 or anchor UE 14 provided during the message exchange can be used to obtain the list of capabilities and / or the recommended values ​​of the configuration parameters of the respective device UE 10 or anchor UE 14.

[0101] The configuration of requirements and parameters is in the form of a set of policy rules (e.g. provided through RRC or through a PCF Policy Container) that define a set of conditions based on which the device will decide which configurations / methods / parameters / values ​​to apply, e.g. conditions defining the minimum measured signal strength above which ranging measurements will be taken on a particular frequency.

[0102] In another example, for example, after the LMF receives information about a ranging constellation (e.g., from an external application (e.g., through the NEF), an LCS client or other core network function that provides the (group / domain) credentials to use), or after dynamically establishing a state in which a set of UEs form a ranging constellation (at which point the LMF, possibly in cooperation with other core network functions, decides which (group / domain) credentials to use), the UEs in the ranging constellation are provided with the (group / domain) credentials and / or authorization tokens upon configuration by the LMF or other management entity. The LMF or other management entity provides the (group / domain) credentials to use for the ranging constellation to the target UE or anchor UE, for example, using the LPP protocol. Alternatively or additionally, the PCF provides the (group / domain) credentials to use for the ranging constellation as part of the UE configuration data, for example, during the initial network configuration or using the UE configuration update procedure specified in 3GPP TS 23.502. Alternatively or additionally, the (group / domain) credentials used for the ranging constellation are stored in the USIM, for example during initial provisioning or during download of the (e)SIM profile.

[0103] Furthermore, when a (new / different) target UE or anchor UE joins a ranging constellation (e.g., to determine the location of the target UE, the LMF or other management entity determines that the target UE is in the vicinity of one or more anchor UEs of the constellation (e.g., based on tracking area or Cell ID information provided during attachment / registration to the network, based on sidelink discovery information received from / by the target UE or anchor UE, or based on the last known position of the target UE), the LMF or other management entity determines that the target UE is part of the same trusted group / domain as other UEs in the constellation (e.g., part of a set of identities provided by the application (e.g., through the NEF) and / or belongs to the same closed access group, non-trusted group, or other trusted group) (e.g., based on the tracking area or Cell ID information provided during attachment / registration to the network, based on sidelink discovery information received from / by the target UE or anchor UE, or based on the last known position of the target UE), the LMF or other management entity determines that the target UE is part of the same trusted group / domain as other UEs in the constellation (e.g., part of a set of identities provided by the application (e.g., through the NEF) and / or belongs to the same closed access group, non-trusted group, or other trusted group). When the target UE determines that the target UE belongs to a public network, a (private) network slice, in response to a request for the target UE or an anchor UE to perform a location estimation for the target UE and / or in response to a request (e.g., by the target UE or an application (e.g., through the NEF)) to add the target UE to the ranging constellation, the target UE is temporarily associated with the ranging constellation, possibly automatically, and thereafter the LMF or other management entity (e.g., the PCF during initial network configuration) provides the target UE or anchor UE with (group / domain) credentials to be used for the ranging constellation. It should be noted that every time a UE joins or leaves a constellation, a new set of group / domain credentials needs to be determined and provided to all remaining UEs in the ranging constellation.

[0104] The provision of the (group / domain) credentials to be used for the ranging constellation is, for example, performed when the target UE or anchor UE successfully connects / registers to a given closed access group, non-public network, network slice, or trusted group / domain, and the result is provided by the involved core network function (e.g., AMF, AUSF, or UDM) to the LMF (or other management entity), and / or the LMF (or other management entity) issues a request to the UDM (or other core network function) to verify, for a given target UE identity or anchor UE identity, whether the target UE or anchor UE can access the given closed access group, non-public network, network slice, and / or trusted group / domain, and / or to verify, by the LMF or other management entity, that the target UE identity or anchor UE identity belongs to the set of UE credentials that also participate in the ranging constellation (provided as part of the ranging constellation configuration information). For this purpose, the LMF (or other management entity) provides the AMF and / or gNB with a protected message or protected container containing information about the (group / domain) credentials and sends it to the respective UE. This can be a separate procedure or the AMF and / or gNB includes this protected message / container as part of the response to the respective UE. Alternatively or additionally, this is part of the authorization procedure for performing ranging (as described in other embodiments). In case of partial coverage or out-of-coverage situations, the protected message or protected container containing information about the (group / domain) credentials is provided to the target UE by the anchor UE (on behalf of the LMF (e.g. issued and protected by its own local subset of LMF functions) or as a message relayed from the LMF).

[0105] In a further example of device configuration to enable ranging, the configuration of the device UE 10 by the management entity is achieved by assigning security key material and ProSe discovery information as described in 3GPP specifications TS 33.303 and TS 33.305. 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 enable integrity protection, scrambling protection, and / or confidentiality protection. The device UE 10 is also provided with an identifier, for example, identifying the 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 associated with the ranging constellation 50 are not static but change over time. In one example, the wireless access device 20 is communicatively coupled to the device UE 10 and / or the anchor UE 14 (possibly in combination with ranging and location services). The device UE 10 reports its device capabilities and application requirements to the RMF 36 and / or LMF 34 or other management entity (e.g., via the wireless access device 20 or via another / head anchor UE connected to the wireless access 20). The anchor UE 14 reports its current configuration and reports information about the current status / evolution of the members of the ranging constellation 50 (such as the number of devices, device identities, device capabilities, estimated locations of devices, estimated speed / mobility of devices, information about device battery levels / capabilities, information about device resource capacities, or information about which devices are in coverage and which are out of coverage) to the RMF 36 and / or LMF 34 or other management entity, either directly (e.g., via the wireless access device 20) or via another / head anchor UE operating the management entity (e.g., via the wireless access device 20) or connected to the RMF 36 and / or LMF 34 or other management entity.The RMF 36 and / or LMF 34 or other management entity configures the device UE 10 and / or anchor UE 14 with a policy that determines the parameters for performing ranging, ranging services, and / or location services, which parameters are based on the (latest) information received about the ranging constellation. If the information about the current status / evolution of the constellation indicates that the number of available anchor UEs of the constellation has decreased since the ranging constellation 50 was established / determined, for example because some anchor UEs have been switched off or moved too far away from other anchor UEs in the constellation, the parameters of the ranging procedure or ranging / location services are adapted to reflect the new situation and reconfigured / updated on each device involved in the ranging constellation 50 and / or device UE 10 utilizing the ranging constellation 50. If it is discovered that the number of anchor UEs for a constellation is insufficient (e.g., in a particular area previously identified as covered by a ranging constellation), the constellation is discarded and information about and / or configuration parameters relating to the constellation are deleted from the device UE 10 and / or anchor UE 14 and from the management entity.

[0106] Additionally or alternatively, the network publishing function 38 is used to control (e.g., by external applications) network level parameters and other parameters / configuration settings required for optimal performance of the intended mobile device ranging and location services. These parameters are combined with configuration parameters received from the involved devices UE 10, anchor UE 14, and / or (other) management entities. In case of overlapping configuration parameters with different values, a priority scheme is applied, whereby configuration parameters received from the devices UE 10, 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, ranging management function 36, and / or other location / ranging services, or their proxies, discard measurements, measurement results, and / or calculated distances / angles, send error messages, and / or send messages to the respective involved devices UE 10 and / or anchor UE 14 to update the configuration parameters.

[0107] Similarly, if the device UE 10 and / or anchor UE 14 receives configuration parameters or desired parameter values ​​to be used that conflict with configuration parameters (e.g. valid value ranges or maximum / minimum values) received from a management entity with a higher priority, 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 parameters, or an exception may be requested from the management entity with a higher priority. In case of multiple management entities, the core network configures a policy that includes the priority rules of the different management entities. Also, conflict resolution may be done on a first-come-first-served basis or may use the configuration received from, for example, the closest anchor UE.

[0108] Ranging-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.

[0109] In one embodiment, ranging or positioning is performed between device UE 10 and anchor UE 14 according to configuration parameters of a management entity in anchor UE 14 or a management entity that provides the configuration parameters directly (e.g., over a Uu or PC5 interface), via anchor UE 14, or via an intermediate device (e.g., a ProSe UE-to-network intermediate). For this purpose, the anchor UE 14 or the management entity exposes to the one or more device UEs 10 and / or one or more other anchor UEs 14 one or more of the configuration parameters and / or values ​​that the anchor UE or the management entity selected and / or decided to use as parameters for performing a ranging procedure for ranging or location services (e.g., ranging method to be used, bandwidth / frequency to be used, number of antennas to be used), for example via a ProSe discovery message and / or by sending the configuration parameters after establishing a sidelink / PC5 connection with the one or more device UEs 10 and / or one or more other anchor UEs (e.g., via a PC5 signaling message, an RRC message, or a direct communication request / accept message, or via an LPP / NRPPa protocol message, whereby these messages are new messages or existing messages with additional / different fields designated for ranging purposes). In another embodiment, the ranging or positioning service is performed by the wireless access device 20, by the core network 30 (e.g., a network controller device), or by a proxy via the anchor UE 14. The devices UE 10 and / or anchor UE 14 involved in ranging / positioning transmit the configuration parameters they selected and / or used to perform the ranging (e.g. ranging method used, bandwidth / frequency used, number of antennas used) (in addition to or separately from the respective distance / angle measurements) to a ranging service (or its proxy), a location service (or its proxy), or a management entity (which collects information from the involved UEs and transmits it to a ranging service or location service).The ranging or location service may use this information to determine how to calculate position / distance / angle estimates, to determine measurement accuracy estimates, thresholds for accepting measurements, measurement / calculation error corrections, and / or to determine configuration changes for one or more UEs involved.

[0110] In one embodiment, to initiate ranging, the device UE 10 sends a signal to the anchor UE 14, or the anchor UE 14 sends a signal to the device UE 10, or in case of a ranging constellation consisting of more than two UEs, the device UE 10 or the anchor UE 14 sends 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 can be a separate signal or message, or indicated by setting an attribute (e.g., a Boolean "rangingrequest" attribute as part of a direct communication request message or RRCSetupRequest) during connection setup between the two UEs. This is typically done during or after the discovery phase, during which the UE acquires configuration parameters (as explained above) and / or possibly other properties of ranging or location services offered by other devices (e.g. supported ranging capabilities, whether to act as an anchor UE, the (preferred) ranging method to use, location information, device identifier, ranging constellation identity / identifier, list of anchor UE identities (for ranging constellations), location information of one or more anchor UEs (for ranging constellations), key identifier, credentials (e.g. public key), nonce, location information, etc.). , V2X, or Sidelink / D2D services, antenna information / configuration).It should be noted that the above mentioned parameters may also be transferred during the (pre-)configuration phase (e.g. received as part of policy information from the PCF when the UE is in coverage) or after discovery, e.g. after a PC5 / sidelink connection is set up (e.g. via PC5 signaling or RRC messages). It should also be noted that when a request to initiate a ranging session is received by one of multiple anchor UEs in a ranging constellation, the anchor UE receiving the request may forward or issue the request to other anchor UEs in the ranging constellation, or may forward or issue the request to a ranging or location service (which in turn may forward or issue the request to other anchor UEs in the ranging constellation).

[0111] In one example, multiple anchor UEs 14 may cooperate to perform sidelink positioning of a target UE 10 in different coverage scenarios. The target UE connects to multiple anchor UEs to perform the ranging procedure. By collecting information from different ranging measurements, a more accurate sidelink position is calculated than if only a single anchor UE is used. These multiple anchor UEs form a so-called ranging "constellation", whereby they have a fixed location and together can cover a certain area, such as a room or a building. The target UE discovers multiple anchor UEs in its vicinity, or a constellation of anchor UEs (with unique identities), and invites all of them to participate in the same ranging session / procedure. Alternatively, the target UE discovers one anchor UE (of the ranging "constellation"), and then the anchor UE or the LMF (or other management entity) invites the other anchor UEs to participate in the ranging session / procedure. For this purpose, information about a session identifier or constellation identifier is exchanged between the involved target UE and anchor UE.Additionally or alternatively, the target UE (or anchor UE) discovers the anchor UE (A1), and the anchor UE (A1) may include in its discovery response message (or in a PC5 groupcast / multicast / broadcast message, or via a PC5 unicast link between the target UE (or anchor UE) and the anchor UE (A1) using, for example, an extended encapsulated LPP assistance or similar command) identities of other anchor UEs in the vicinity (e.g., discovered by the anchor UE (A1)) (e.g., L2 identities in a discovery or direct communication request, or L2 groupcast / multicast / broadcast identifiers). ), and possibly other information about other anchor UEs in the vicinity, to the target UE (or anchor UE) (e.g., as part of metadata fields in a discovery message from that anchor UE (A1) to the target UE), so that the list is subset to include only anchor UEs of the ranging constellation, so that the target UE (or anchor UE) can perform targeted discovery (e.g., by including identifiers of the anchor UEs to be discovered in its discovery request message) and / or directly issue DCR messages to connect to these anchor UEs without having to discover the anchor UEs first. Additionally or alternatively, the LMF (or other management entity) may request one or more anchor UEs 14 to perform discovery of the target UE 10, after which the anchor UEs establish ranging connections with each other and participate in the ranging session / procedure.

[0112] In one example, the LMF (or other management entity) instructs each invited anchor UE to use the same session identifier or constellation identifier by including such identifier when setting up the connection or when sending a message to initiate ranging with the target UE 10. In another example, the target UE 10 derives a single session identifier or constellation identifier itself using the information it has received about the constellation and includes this identifier when setting up the connection or sends a message to initiate ranging to each anchor UE that matches the identity of the anchor UE in the constellation or that has provided a constellation identifier that matches the constellation identifier through a discovery announcement or discovery response. The anchor UE 14 provides a session identifier (e.g., provided by the LMF or other management entity as part of an invitation to participate in the ranging session procedure or as part of the anchor UE's configuration information) through its discovery announcement or discovery response, and the target UE 10 compares the session identifier with the known session identifiers. If the session identifier matches a known session identifier, the target UE 10 identifies the discovered anchor UE 14 as an additional anchor UE that is part of the constellation, and therefore sets up a connection with that anchor UE to join a ranging session using that session identifier, or sends a message to initiate ranging using that session identifier.

[0113] In another example, the anchor UEs of a ranging constellation are configured / invited to participate in ranging and / or location estimation of the target UE, but do not need to actively set up a ranging session with the target UE. This is done by the LMF 34 or RMF 36 (or other management entity) providing configuration information to each anchor UE of the ranging constellation, including information about PRS / SRS or other ranging reference signals used by the target UE or other anchor UEs (e.g., signal characteristics / type, resource schedule, frequency band / bandwidth used, etc.). This information can be used to monitor relevant signals, perform measurements on these signals if they are received (e.g., determine the time of arrival at the respective anchor UE), and report these measurements (or calculated ranging results such as distance or angle) to the LMF 34 or RMF 36 or their proxies. The configuration information provided to each anchor UE includes identifiers of the target UE or other anchor UEs, or identifiers related to the ranging reference signal configuration or configuration items therein (e.g., specific resource schedules), which the anchor UE uses when reporting measurements / ranging results to the LMF 34 or RMF 36 or their proxies by associating a specific reception of the relevant signal with this identifier. The timing of the measurement, the signal characteristics, or the frequency used is sufficient information for the anchor UE to determine which ranging procedure the measurement applies to or to which other UEs based on this configuration information, so that the anchor UE can decide which identifier it uses when reporting. The configuration information also includes information about the PRS / SRS or other ranging reference signals that each anchor UE should use to transmit the ranging reference signals (e.g., signal characteristics / type, resource schedule, frequency band / bandwidth used, etc.). The target UE is configured by the LMF 34 or RMF 36 or other management entity with a similar configuration to receive those signals, but is not configured to have information about the anchor UEs that actually transmit those signals.Instead, the target UE is configured to have identifiers associated with the ranging reference signal configuration or configuration items therein (e.g., specific resource schedules), which the target UE uses when reporting measurements / ranging results to the LMF 34 or RMF 36 or their proxies by associating a specific reception of the relevant signal with this identifier. The timing of the measurement, the signal characteristics, or the frequency used is sufficient information for the target UE to determine which ranging procedure the measurement applies to or to which other UEs based on this configuration information, so that the target UE can decide which identifier the anchor UE uses when reporting. The configuration information also includes the relevant security credentials to be able to decrypt or encrypt the payload of a specific signal. Since the target UE does not even need to know that another anchor UE is involved in ranging and / or location estimation of the target UE, the LMF 34 or RMF 36 or their proxies need to ensure that the anchor UE is authorized to be involved in ranging of the target UE and / or that the target UE agrees to this. As mentioned in other embodiments, the target UE gives consent for each anchor UE to participate in ranging of the target UE, or for all anchor UEs in the constellation at once. The LMF 34 or RMF 36 or their proxies must verify the consent given to the anchor UE, ensure that the anchor UE is properly authenticated and / or authorized, and provide configuration information to each anchor UE, including information about PRS / SRS or other ranging reference signals used by the target UE or other anchor UEs.

[0114] In yet another example, the target UE discovers multiple anchor UEs, sets up a connection, and initiates a ranging session with each anchor UE separately using a separate session identifier. The target UE reports these session identifiers, the set of anchor UE identifiers with which the target UE performed ranging, and / or ranging measurements or results to the LMF 34 or RMF 36 or their proxy (either directly if the target UE is in coverage or via the anchor UE forwarding or issuing messages if the target UE is out of coverage). The LMF 34 or RMF 36 or their proxy determines, based on the anchor UE identifiers, for each identifier, whether it corresponds to an anchor UE identifier in one or more ranging constellations. In this way, the LMF 34 or RMF 36 or their proxy can determine whether all anchor UEs of a ranging constellation have been discovered by the target UE and / or whether the target UE has performed ranging with that anchor UE. If all anchor UEs are not discovered, the LMF 34 or RMF 36 or their proxies instruct the target UE to discover and / or connect to the remaining anchor UEs in the constellation, and / or configure and / or invite the remaining anchor UEs to discover the target UE and / or perform ranging with the target UE.

[0115] In another embodiment, which may be combined with any other embodiment or implemented independently, before the start of a ranging session (e.g., during discovery) or during a ranging session, the target UE 10 receives identification information of each anchor UE 40. If the identification information matches one of the anchor UE identification information in one or more ranging constellations in the ranging constellation information received by the target UE (e.g., from a management entity during (pre)configuration), the target UE checks whether it has discovered all anchor UEs of the respective constellations and / or connected to all anchor UEs of the respective constellations to perform ranging. If not, the target UE initiates discovery or connection setup for the remaining anchor UEs of the respective constellations that the target UE has not yet discovered or performed ranging with. If the remaining anchor UEs cannot be discovered or connected, the anchor UEs are out of range of the target UE (i.e., too far from the target UE). This information (i.e., the anchor UE is out of range) can be used in the calculation to determine the location of the target UE, together with the constellation area information and / or the location information of the anchor UE, since it would rule out that the target UE is close to the anchor UE and must be somewhere else.This calculation is done e.g. by excluding circular, elliptical or hyperbolic areas / volumes around the anchor UE whose radius, semi-minor axis and focal length minus the semi-major axis are less than or equal to the (expected / calculated) wireless signal range of the target UE for the length of sidelink communication (at a given frequency), or by excluding e.g. the area behind an "imaginary" line (or further parallel lines) between two other anchor UEs from which the target UE was able to calculate its distance, or by excluding e.g. a set of circular areas centred on the target UE and with a radius of the sidelink wireless signal range and including the anchor UE (e.g. as a point on a circle) but not including one or more of the other anchor UEs from which the target UE was able to discover and calculate its distance, or by excluding e.g. parts of the indicated area for the ranging constellation that are not near the anchor UEs from which the target UE was able to discover and perform ranging. Additionally or alternatively, the target UE reports to the LMF (or other management entity) the anchor UE identity with which it has discovered or performed ranging (either directly if the target UE is in coverage or via an anchor UE forwarding or issuing a message if the target UE is out of coverage). The LMF determines the constellation to which the discovered anchor UE belongs based on the received identity. If the target UE has not reported that it has discovered or was able to discover or perform ranging with one or more other anchor UEs of such a constellation, this anchor UE identity will exclude that the target UE is close to the anchor UE and must be somewhere else, so the LMF can use this anchor UE identity in its calculations to determine the location of the target UE.Additionally or alternatively, the anchor UE reports to the LMF (or other management entity) that it has discovered the target UE, that it is attempting to discover the anchor UE, that a connection is being established or has been established between the target UE and the anchor UE (e.g., to perform ranging), that the anchor UE has not discovered the target UE, or that the target UE is not attempting to discover or establish a connection with the target UE. If the target UE has not been discovered or is attempting to discover the respective anchor UE, the LMF can use these information in its calculations to determine the location of the target UE, since this would exclude that the target UE is near the anchor UE and must be somewhere else. In other words, the LMF or the location service proxy (also called positioning service proxy) uses information about the inability to discover or connect to the anchor UE of the constellation from the target UE and / or anchor UE to exclude target UEs (or anchor UEs) that are in a location near the anchor UE that cannot be discovered or connected to.

[0116] As mentioned above, sidelink positioning should work in various coverage scenarios. In one embodiment, which may be combined with any other embodiment or implemented independently, when the target UE and the anchor UE are within the coverage of the NG-RAN, the target UE connects to the LMF and indicates its intention to collect measurements at the target UE and calculate the target UE's location, or indicates its intention to have the LMF or a location service proxy calculate the target UE's location. In the former case, the anchor UE provides the measurements and information about their location (or reference plane / reference angle information) to the target UE. The target UE needs to be authorized to receive the anchor UE's location. In the latter case, the anchor UE provides the measurements and information about their location to the LMF or another anchor UE (e.g., head anchor UE) for processing to calculate the target UE's location. In that case, the target UE needs to transmit its measurements to the LMF or anchor UE. The LMF configures the target UE and the anchor UE accordingly, sends a response to the target UE confirming or rejecting the target UE's intention, and / or provides instructions or policy information to the target UE based on which the target UE decides on its subsequent actions. Additionally or alternatively, the target UE indicates its intention (e.g., while initiating a ranging session with the anchor UE) or sends configuration data (e.g., in accordance with the target UE's intention) directly to the anchor UE.

[0117] Similarly, in a variant of the embodiment, to support partial coverage situations, for example when the target UE is out of coverage and the anchor UE (at least one of the anchor UEs) is in the coverage of the NG-RAN, the target UE connects to one or more anchor UEs and indicates its intention to collect measurements at the target UE and calculate the target UE's location, or indicates its intention to have the LMF calculate the target UE's location. In the former case, the anchor UE provides the target UE with information about those measurements and their location (or reference plane / reference angle information). The target UE must be authorized to receive the anchor UE's location (or reference plane / reference angle information). In the latter case, the anchor UE provides the LMF with information about those measurements and their location (or reference plane / reference angle information). The target UE must also send its measurements to the LMF, but if the target UE is out of coverage, the anchor UE must forward the measurements, for example by using the UE-to-network relay function of ProSe. The anchor UE (e.g., head anchor UE) or the LMF responsible for calculating the target UE's location (e.g., indirectly via the anchor UE) configures the target UE and anchor UE accordingly, sends a response to the target UE confirming or rejecting the target UE's intention, and / or provides instructions or policy information to the target UE based on which the target UE decides on its subsequent actions.

[0118] In another embodiment variant, to support partial coverage, out-of-coverage and in-coverage situations, the anchor UE supports a subset of the LMF's capabilities (i.e. acts as a location service proxy) and collects ranging measurements to calculate the target UE's location (as shown in FIG. 8). The anchor UE should be able to indicate this capability to the target UE, e.g. during discovery, or have the LMF or location service proxy calculate the target UE's location as a response to the target UE's request / intention. If the target UE agrees, it can send its measurements to the respective anchor UE. If multiple anchor UEs are involved in the sidelink positioning, one of the anchor UEs is selected and the other anchor UEs should send their measurements and locations to the selected anchor UE. The anchor UE should be authorized to receive the target UE's measurements and the measurements and locations of the other anchor UEs and to calculate the target UE's location. In order to calculate the location of the target UE using as many measurements as possible, it is important that an anchor UE supporting a subset of the LMF capabilities (e.g., the ability to calculate location) is in coverage or can connect directly (on PC5) or indirectly (e.g., via a base station or core network via Uu, or via an intermediate device on PC5) to other anchor UEs (e.g., other anchor UEs in the ranging constellation) and the target UE. Thus, the anchor UE indicates during discovery (e.g., in a message field during Model A / B discovery) how many other anchor UEs it is or can connect to directly or indirectly. The anchor UE also indicates connection quality / speed / latency metrics such as signal quality, error rate, number of hops, minimum / average / maximum latency, congestion rate, distance, line-of-sight connection between UEs (or, for example, no obstacles detected). The target UE uses this metric as a selection criterion to select the anchor UE.The anchor UE also indicates whether it has a stable connection to the base station / core network (e.g., signal quality is good, the anchor UE is not currently moving) and indicates that it expects or calculates (e.g., through signal analysis or other sensors) that it has a line-of-sight connection to the target UE. Additionally or alternatively, the anchor UE uses one or more of the above-mentioned indicators (discovered from one or more other anchor UEs) and other information about the other anchor UEs, such as the capabilities of the other anchor UEs (e.g., detected or provided during connection setup), to negotiate with other anchor UEs which anchor UE should act as a head anchor UE, which anchor UE will calculate the location of the target UE, which anchor UE will announce that it supports a subset of the capabilities of the LMF, and / or which anchor UE will connect to the LMF. Such negotiation is triggered by the anchor UE when it detects that it is not in the coverage of the network or when it detects (e.g., through discovery of other anchor UEs) that one or more other anchor UEs are not in the coverage. The criteria for the condition to start such negotiation is determined based on a preconfigured policy, an instruction / policy provided by the LMF before or at the start of the ranging session. Additionally or alternatively, the anchor UE uses one or more of the above-mentioned indicators (discovered from another anchor UE or UEs) and other information about the other anchor UEs, such as the capabilities of the other anchor UEs (e.g., detected or provided during connection setup), to determine whether to act as a head anchor UE, whether to calculate the location of the target UE, whether to announce that it supports a subset of the capabilities of the LMF, and whether to connect to the LMF. Such a determination is triggered by the anchor UE when it detects that it is not in coverage of the network or when it detects (e.g., through discovery of other anchor UEs) that one or more other anchor UEs are not in coverage.The criteria for the condition to start such negotiation is determined based on a pre-configured policy, an instruction / policy provided by the LMF before or at the start of the ranging session. Additionally or alternatively, the target UE is in coverage and can connect to the LMF. The target UE indicates to the LMF its intention to calculate its location. The LMF determines that one or more anchor UEs are currently out of coverage based on ranging constellation information and / or information about discovered anchor UEs (e.g., provided by the target UE). Thus, the LMF cannot communicate with these anchor UEs to obtain or identify their location. The LMF instructs the target UE to calculate its location itself or to use a location service proxy instead, or requests the target UE to obtain and / or forward location information and / or measurement data about the anchor UE to the LMF. Additionally or alternatively, the LMF calculates the location of the target UE based on the last known location information from the respective anchor UE and indicates to the target UE that the location of the target UE has been calculated based on old information and / or is inaccurate. Additionally or alternatively, the target UE indicates in a message to the anchor UE that the target UE is in the coverage of the network and / or has established a connection with the LMF or its proxy, an intention or indication to calculate the location at the LMF or its proxy or the target UE itself (e.g. based on a message from the LMF), and / or a configuration or other indication that the target UE received from the LMF or its proxy for the anchor UE. The anchor UE uses this information to transmit ranging / sidelink positioning measurements and / or location calculation results to the target UE or to the LMF via the target UE, e.g. when the anchor UE itself is out of coverage.

[0119] After or upon receiving the signal to start the ranging session, the involved UEs verify whether the request is from an authorized UE. For this purpose, the UEs need to exchange credentials and perform authentication and / or authorization, either alone or supported by the core network, e.g., connect to the core network to authenticate the involved UEs and verify their authorization. Upon successful authorization, one or more of the UEs start transmitting ranging reference signals (e.g., position reference signals / sounding reference signals or other signals (e.g., ProSe discovery messages)), possibly using radio spectrum resources for sidelink communication or sidelink discovery. This is a signal that is repeated a configured number of times (e.g., with a certain pause / quiet interval between signals) or until a signal to stop the ranging session is received. The (required) timing of these signals (e.g., start time of the first signal) depends on or is determined by configured timing / delays, transmission and reception of synchronization signals, detection of stationary periods, QoS or Quality of Experience (QoE) information (e.g., of ranging / location services or, e.g., of other traffic), scheduled resources (e.g., semi-persistent resources), DRX / sleep information configured and / or exchanged between devices, timing randomization functions, signal quality measurements, Doppler shift / coherence time / hysteresis of measured signals, device velocities, etc. The device UE and / or anchor UE 14 perform ranging measurements on received ranging reference signals (e.g., determine the time of arrival of the ranging reference signals, measure the angle of arrival of the ranging reference signals), and calculate a distance or angle (e.g., between the device UE and anchor UE) or a location estimate (e.g., the position of the device UE) based on the techniques of the above or other embodiments.

[0120] In other words, according to the general definition of the invention on which these embodiments are based, it is proposed to envisage an apparatus for obtaining a location estimate of a target mobile device in a wireless network, the apparatus being adapted to: - Request ranging services from a ranging constellation formed by one or more ranging-enabled anchor devices of the wireless network, which acts as a proxy for the positioning services offered in the geographical area. - Receive at least one response message from the ranging constellation (e.g., a session acknowledgement, a configuration message, a message containing information about the location of the anchor UE). - performing range or location estimation or ranging measurements based on the at least one response message. - Forwarding range or location estimates or ranging measurement results to ranging constellations to support positioning services. Alternatively, it is proposed that an apparatus for obtaining a location estimate of a target mobile device in a wireless network is envisaged or the apparatus is adapted to: - Request ranging services from a ranging constellation formed by one or more ranging-enabled anchor devices of the wireless network, which acts as a proxy for the positioning services offered in the geographical area. - Transmit a ranging reference signal that can be received by an anchor UE 14 of the ranging constellation (e.g., the anchor UE 14 of the ranging constellation performs ranging measurements on the received ranging reference signal and calculates an estimate of distance, angle, or location). - Receive at least one response message from the ranging constellation 50 (e.g., including a calculated range, angle, or location estimate).

[0121] In an example embodiment, the anchor UE may perform a subset of LMF functions (e.g., capability exchange, providing assistance data, calculating ranging / sidelink positioning results (e.g., location of target UE), and / or publishing ranging / sidelink positioning results), i.e., acting as a proxy for the positioning service. In this case, the target UE may perform discovery and selection of such anchor UEs that support being a proxy for the positioning service, which support is indicated during discovery (e.g., indicated as support of SL Positioning Server UE / role during ProSe / V2X discovery over PC5). The target UE may then issue or receive a ranging / SL positioning request using a ranging sidelink positioning protocol (e.g., RSPP) over a PC5 connection between the target UE and the respective anchor UE. The ranging / SL positioning request may include information about the selected anchor UE involved in the ranging / SL positioning procedure with the target UE. The anchor UE itself may also select one or more additional anchor UEs to be involved in ranging of the target UE (e.g., based on constellation information and / or discovered anchor UEs in the vicinity). The proxy function operated by the anchor UE may perform a capability exchange using RSPP over a PC5 connection with the target UE and other selected anchor UEs (if present) and provide ranging / sidelink positioning assistance data to the target UE and other selected anchor UEs (if present). In this case, the target UE and other selected anchor UEs (if present) send their ranging / SL positioning measurements and / or location information to the respective anchor UE operating the proxy function. This depends on whether sharing of location information to other anchor UEs is enabled / allowed per the privacy profile of the other selected anchor UEs.This anchor UE can calculate a ranging / SL positioning result (e.g., the location of the target UE) based on the received ranging / SL positioning measurements and / or location information received from the target UE and other anchor UEs, along with its own measurements and location, and the anchor UE can then publish the result to the target UE or other entities authorized to receive the ranging / SL positioning results. Before initiating a ranging procedure, participating in a ranging procedure, or sharing measurements or location data with the respective anchor UE, the target UE and other selected anchor UEs need to authenticate the anchor UE and / or verify authorization for the anchor UE to act as a proxy for positioning services.

[0122] In an alternative embodiment, which may be combined with other embodiments or implemented independently, the target UE may perform a subset of the LMF functions, i.e., act as a proxy for the positioning service. In this case, the target UE may initiate ranging / SL positioning directly with the discovered and selected anchor UE. For this purpose, the target UE may use a ranging sidelink positioning protocol (e.g., RSPP) over a PC5 connection between the target UE and the respective anchor UE and indicate support for being a proxy for the positioning service in the ranging / sidelink positioning capability exchange, which support is indicated as support for SL positioning server UE / role in the capability exchange. Based on this information, the selected anchor UE may decide whether to transmit their ranging / SL positioning measurements and their location information to the target UE or not. Before initiating a ranging procedure, participating in a ranging procedure, or sharing measurements or location data with the respective target UE, the anchor UE needs to authenticate the target UE and / or verify the authorization for the target UE to act as a proxy for the positioning service. The sharing of location data by the anchor UE to the target UE also depends on whether sharing of location information to the target UE is enabled / allowed per the privacy profile of the anchor UE. The target UE acting as a positioning service proxy can provide ranging / sidelink positioning assistance data to the selected anchor UE using RSPP over a PC5 connection, after which the target UE can calculate the ranging / SL positioning result (e.g. its own location) based on the received ranging / SL positioning measurements and location information received from the anchor UE along with the target UE's own measurements. If required / supported, the target UE can publish the ranging / SL positioning results to other entities authorized to receive them.

[0123] In another alternative embodiment, which may be combined with other embodiments or implemented independently, a device that is neither a target UE nor an anchor UE (e.g., a device outside the ranging constellation) supports a subset of LMF functions, i.e., acts as a proxy for positioning services. In this case, the target UE may perform discovery and selection of such devices that support being a proxy for positioning services, and this support is indicated during discovery (e.g., indicated as support of SL positioning server UE / role during ProSe / V2X discovery over PC5). The target UE may then issue or receive a ranging / SL positioning request using a ranging sidelink positioning protocol (e.g., RSPP) over a PC5 connection between the target UE and the respective device. The ranging / SL positioning request may include information about the selected anchor UE involved in the ranging / SL positioning procedure with the target UE. The proxy function operated by the respective device may perform a capability exchange with the target UE and the selected anchor UE using RSPP over the PC5 connection and provide ranging / sidelink positioning assistance data to the target UE and the selected anchor UE. In this case, the target UE and the selected anchor UE send their ranging / SL positioning measurements and / or location information to the respective device operating the proxy function. This device can calculate the ranging / SL positioning result (e.g., the location of the target UE) based on the received ranging / SL positioning measurements and / or location information received from the target UE and anchor UE together with its own measurements and location, and the device can then publish the result to the target UE or other entities authorized to receive the ranging / SL positioning result. Before initiating a ranging procedure, participating in a ranging procedure, or sharing measurements or location data with the respective devices, the target UE and other selected anchor UEs need to authenticate the device and / or verify authorization for the device to act as a proxy for the positioning service.The sharing of location data by the anchor UE to separate devices supporting a subset of LMF capabilities also depends on whether sharing of location information to such devices is enabled / allowed per the privacy profile of the anchor UE.

[0124] In another embodiment, the signal to initiate the ranging session is sent by the access device or core network function (such as the Location Management Function 34 and / or the Ranging Management Function 36) to the involved UE or UEs. In one example, the access device and / or core network function knows that two UEs are in close proximity (e.g., because both are connected to the same access device), and as a result, the access device or core network function instructs the two UEs to initiate a ranging session without the UEs having to perform a discovery phase. The access device or core network function provides 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 identifiers and / or credentials to use during ranging, etc.), and also indicates the exact timing and order in which each UE is supposed to transmit signals.

[0125] It should be noted that the embodiments describing the device UE10 discovering and / or performing a ranging session with the anchor device UE14 may be equivalently replaced with embodiments in which the two devices UE10 discover and / or perform a ranging session with each other.

[0126] Anchor UE self-configuration In one embodiment, which may be combined with any other embodiment or implemented independently, if the device UE 10 detects that there is no anchor UE 14 in its vicinity, if the device UE 10 is qualified by a management entity (e.g., based on a set of preconfigured policies) to behave as an anchor UE, and / or if the device UE 10 has good coverage of location services at its current location (e.g., detects multiple access devices in the vicinity transmitting position reference signals with good signal strength, has a stable connection to a location service (e.g., LMF) operated by the core network via one or more access devices), and / or has additional means of acquiring location coordinates (e.g., through an internal GPS module), the device UE 10 can configure itself as an anchor UE 14. Upon self-configuration as an anchor UE, the device UE 10 can start advertising a ranging constellation and / or transmit a ranging reference signal. Before self-configuring as an anchor UE, the device UE requests and / or receives approval to become an anchor UE from a lead anchor UE and / or a management entity, and / or requests / receives anchor UE-related configuration information. Self-configuration by the UE to become an anchor UE is initiated when another device UE 10 (or anchor UE 14) initiates discovery of the UE or initiates a ranging session / procedure with the UE, or when the UE initiates discovery of another 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 the criteria defined by a set of pre-configured policies, the UE indicates to the other device UE 10 (or anchor UE 14) its role as an anchor UE or its intention to become an anchor UE when performing discovery or establishing a ranging session.

[0127] In one example, the UE itself decides to become an anchor UE 14, for example based on a set of policies, and reports this to the management entity. To enable this, the UE is provisioned (possibly in order of priority) with policies / criteria based on which it decides whether it can act as an anchor UE 14 (e.g., an attribute in a discovery message, a connection setup message, or a ranging session setup message can be set to a value that indicates that the UE is capable / valid to be an anchor UE). Such policies / criteria may include whether the UE has the ability to determine its location (e.g., via GNSS), whether the UE's location is stable (e.g., with a certain allowable deviation threshold and / or fluctuating within a sufficiently small (geographical) area), whether the UE is moving at a fixed speed or at a speed that varies between a minimum and a maximum deviation threshold, whether the signal quality / strength of the positioning / ranging reference signal or the signal from the access device measured by the UE exceeds a certain minimum threshold, the Doppler shift / hysteresis of the positioning / ranging reference signal or the signal from the access device measured by the UE (possibly expressed in dB in addition to the signal strength / quality threshold), etc. The UE may also be configured to use a scaling factor, whereby the scaling factor is different for different (relative) velocities, within a particular threshold; whether the UE is within the coverage of a base station or connected to a particular network (e.g., a home PLMN); whether the UE has a connection with a location / ranging service; whether the UE supports an accurate clock; whether the UE is synchronized to a particular reference clock; which ranging mechanisms the UE supports (e.g., TDOA, round trip time); which sensors the UE supports (e.g., barometric pressure sensor, gyroscope); and / or how many antennas the UE has / supports.The configuration of the policies / criteria may vary (e.g., different sets of parameters or different values) for different capabilities and / or different situations of the anchor UE, such as whether the UE can act as a proxy for location services (e.g., whether the UE can support a subset of the capabilities of the LMF), whether the UE can act as a location reference unit, whether the UE is within range of the network, whether unlicensed or licensed spectrum is available / used, which tracking area / cell / registration area / country the UE is in, whether it is connected to a visited or home PLMN. After the UE determines that it can act as an anchor UE 14, it reports this to a management entity or reports its role as an anchor UE or its intention to become an anchor UE to another device UE 10 (or anchor UE 14) when performing detection, establishing a ranging session / procedure, or during the ranging session / procedure. The UE also switches on / off certain ranging-related capabilities, such as the ability to act as a proxy for location services, based on whether one or more of the above-mentioned policies / criteria are met.

[0128] In one example, a ranging capable UE can already determine and / or provide its (desired) role or at least the ability to perform a certain of its roles (e.g., anchor UE) during discovery. A device UE 10 that cannot become an anchor UE 14 should be able to limit its discovery to find only other ranging capable UEs that can become anchor UEs. If it is not clear at the time of discovery whether a discovered ranging capable UE is or can become an anchor UE, it is a waste of time and resources to try to set up a connection with the discovered ranging capable UE and start a ranging session / procedure. The desired or possible role of a ranging capable UE, specifically whether a ranging capable UE can be an anchor UE and / or whether a ranging capable UE can / can act as a location service proxy, is not static but changes depending on the situation. For example, even if a ranging capable UE includes a GNSS module for position determination, the ranging capable UE may be outside the coverage of a GNSS satellite network (e.g., indoors or in a tunnel) and therefore cannot become an anchor UE and / or cannot act as a location service proxy. Similarly, if a UE is out of the coverage of the NG-RAN, it cannot become an anchor UE and / or cannot act as a location service proxy. Also, the UE's location may be too unstable (e.g., the UE is moving too fast or shaking too much) to be used as an anchor UE. To this end, it is necessary to consider configuring and applying a policy by which a ranging capable UE determines its possible roles. Such a policy may be configured by the LMF (or PCF, or other core network function). Possible criteria / conditions to be considered for a ranging capable UE to switch on / off its role as an anchor UE, to switch on / off the indication that the ranging capable UE's location is known or identifiable, and / or to switch on / off its ability / capability to provide a location service proxy include: - whether the UE has a position fix (e.g., via GNSS), how long the location is expected to remain valid, when the location was last determined, and / or how often the location is updated - what methods / capabilities are used to determine the UE's location (e.g., GNSS support) and / or the accuracy of such methods / capabilities; - Whether the UE's location is stable or not (e.g. whether the UE is stationary or moving, which is determined by a set of limits / thresholds (e.g. the UE is moving at a very slow or constant speed, or the UE's location is fluctuating within a small confined area), these limits / thresholds are determined by a set of criteria) - Whether the UE is within the coverage of the base station - whether the UE is connected to an LMF or not - Whether the UE receives sufficient positioning / ranging reference signals Similarly, when a rangeable UE is in the coverage of the network and connected to the LMF (or RMF, or other management entity), the LMF (or RMF, or other management entity) determines the role of the rangeable UE based on similar criteria / conditions. If the situation changes during the ranging procedure, the role of the rangeable UE also changes. Such role change needs to be notified to other UEs involved in the ranging procedure and also to the LMF (or RMF, or other management entity) if it is in coverage. In one example, the target UE, LMF, GMLC, or application determines the desired / expected accuracy of the target UE's location estimate and / or whether a geographical location or a relative location (with respect to a reference point) is desired / expected and indicates this in a location request to the LMF, target UE, location service proxy, and / or one or more anchor UEs. Based on the desired / expected accuracy and / or the type of location required (e.g., geographical or relative location), - Depending on one or more of the above criteria / conditions, the anchor UE announces or stops announcing that it is an anchor UE, announces or stops announcing that its location is known or identifiable, and / or announces or stops announcing that it can provide a location services proxy. - The target UE, the Location Service Proxy, the LMF and / or one or more anchor UEs decide not to use the anchor UE's location depending on one or more of the above criteria / conditions.

[0129] Additionally or alternatively, the anchor UE may indicate to the target UE, the location service proxy, the LMF, and / or one or more other anchor UEs a measure of the accuracy of its location estimate (e.g., maximum deviation), which depends on the method / capability used to determine the anchor UE's location.

[0130] Additionally or alternatively, the LMF, location service proxy, or other entity that calculates the location based on the estimated location of the anchor UE may indicate to the target UE, GMLC, application, or other entity that receives the target UE's location estimate a measure of the accuracy of the target UE's location estimate (e.g., maximum deviation), depending on the method / capability used to determine the anchor UE's location.

[0131] Additionally or alternatively, the anchor UE may provide further details related to the stability and accuracy of its location in message exchanges with the target UE, the LMF, the location service proxy or the management entity and / or inform or express this change in capabilities to the target UE, the LMF or the location service proxy (e.g. when the anchor UE is no longer able to provide its location, i.e. when it is no longer able to play the role of a located UE, e.g. due to loss of GNSS coverage), e.g. by extending the "ProvideCapabilities" message of the LPP protocol, whereby the capabilities are described by using fields / arguments defining the current role of the anchor UE (e.g. role="located UE") and / or whether the anchor UE has a known location or whether its location can be determined (e.g. location="available"), whereby the same or similar fields / arguments are used to define a change in role (e.g. role="reference UE", role change="reference UE", or location="unavailable"). Similarly, the anchor UE may indicate in such capability exchange the (average) accuracy of its location (e.g., accuracy="10 meters"), the (average) refresh time between location updates / new position fixes (e.g., refresh="1 second"), the (average) validity time for which the position is stable (e.g., validity time="10 seconds"), the (average) latency for determining an update to its location (e.g., latency="0.5 seconds"), and / or other relevant parameters.The anchor UE also uses the same message to indicate whether or not it will share its location with the entity receiving the message (e.g., the entity sending the "RequestCapabilities" message, which the anchor UE will send a "ProvideCapabilities" message in response) based on its privacy profile, for example by including the field / argument location-info="private" or location-info="public", such that such a message also includes additional information regarding with which entities the anchor UE can share its location position (e.g., a group ID to indicate that the anchor UE will only share its location with members of the same group). Similarly, the anchor UE may provide further details related to the stability and accuracy of its location in message exchanges with the target UE, the LMF, the Location Service Proxy, or the management entity, inform or express this change in capability to the target UE, the LMF, or the Location Service Proxy (e.g., when the anchor UE is no longer able to provide its location, i.e., when it is unable to take on the role of a located UE, e.g. due to loss of GNSS coverage), and / or provide information regarding whether and / or with which entities the anchor UE will share its location with the entity receiving the message, e.g., by using an extended ProvideAssistanceData, ProvideLocationInformation, or other (LPP-based) message. Additionally or alternatively, some ProSe / V2X message may be used, e.g., a Link Modification Request, to indicate the role change.

[0132] It should be noted that the determination of whether the anchor UE's position is stable is 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 receives speed and direction information from one or more nearby device UEs 10 or anchor UE 14, or receives such information from a location service. The UE compares the received speed and direction information and then determines 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 reports its speed and / or direction information and / or its location to a location service or management entity (e.g., on another UE), which determines whether the UE is moving within a maximum relative speed difference or maximum direction difference with some other UEs based on the speed and / or direction information of the other UEs, and if so, reports to the UE that the UE can become an anchor UE and configures the UE as such. If it determines that the UE can become an anchor UE or after the UE has become an anchor UE, the management entity is notified and adds the UE as an anchor UE to the ranging constellation based on this. The management entity configures the UE as an anchor UE (e.g., configures ranging reference signals, resource scheduling information, provides information about the constellation if it is capable of acting as a proxy for the LMF 34 or RMF 36, etc.) and updates other UEs in the ranging constellation about the newly added anchor UE (e.g., by sending a new configuration). A UE, e.g., an anchor UE, during discovery, may indicate by message (e.g., in a message / message field in a Model A / B discovery message via PC5) that its location is currently known (e.g., via GNSS), whereby the UE indicates the validity time for which this location or its location is expected to remain valid and / or known.The validity time depends on the absolute velocity of the anchor UE, or on its relative velocity and / or direction with respect to the target UE or reference point. This can be useful because the anchor UE is mobile and therefore its location is not always stable. Additionally or alternatively, the UE indicates its velocity and / or direction in messages between the target UE and the anchor UE, for example in its discovery messages or subsequent messages after connection setup.

[0133] In other words, a device and method are provided in which the device UE 10 is configured to support ranging and is further configured to receive (e.g., from a management entity) a set of policies / criteria for determining whether the device UE 10 can act as an anchor UE, perform a series of measurements on received RF signals, based on the measurements the device UE 10 can identify or obtain its location, based on the measurements the device UE 10 can determine whether its location is sufficiently stable according to the set of policies / criteria, based on the measurements the device UE 10 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 start a procedure to request to become an anchor UE 14 and / or to be configured as an anchor UE 14.

[0134] In further embodiments, which may be combined with any other embodiment or implemented independently, the device UE 10 may stop working as an anchor UE if it detects the presence of multiple anchor UEs 14 in its vicinity (e.g. by performing ranging device discovery via a sidelink whereby a discovery message indicates the presence of an anchor UE, e.g. through a field indicating a ranging device type or through a field indicating a ranging constellation identifier) ​​and / or if the device UE 10 measures good coverage of location services at its current location (e.g. if it detects multiple access devices in the vicinity transmitting position reference signals with good signal strength or if it has a stable connection to a location service (e.g. LMF) operated by the core network via one or more access devices) and / or has additional means of obtaining location coordinates (e.g. through an integrated GPS module).

[0135] In one example, the UE is configured (e.g., through a set of policies received from a management entity) to stop working as an anchor UE when the UE detects that there are multiple anchor UEs 14 in its vicinity, when the UE measures good coverage of location services at its current location, and / or when the UE determines that at least a certain number of criteria (e.g., one or several of the above criteria based on which the UE decides to act as an anchor UE) are no longer met. When it is determined that the UE can stop being an anchor UE, or the UE changes its role, e.g., as represented in a field representing the ranging / positioning role of each UE during discovery, from an anchor UE that can determine the UE's location (e.g., a located UE) to an anchor UE that cannot determine the UE's location (e.g., a reference UE), or when the UE indicates during discovery that its location data is not stable or that one or more of its location determination capabilities (e.g., GNSS) are (temporarily) unavailable, and / or after the UE stops being an anchor UE or its role is changed, the management entity is notified and removes the UE from the ranging constellation based on this notification. The management entity updates other UEs in the ranging constellation about the deleted UE or the UE's changed role (eg, by sending a new configuration).

[0136] In other words, devices and methods are provided in which the anchor UE 14 is configured 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 or determination of the locations of multiple anchor UEs, initiate a procedure to cease functioning as an anchor UE 14 and / or request to cease being an anchor UE 14.

[0137] In further embodiments, which may be combined with any other embodiment or implemented independently, a UE of a ranging constellation (e.g., device UE 10 or anchor UE 14) is configured (e.g., by a management entity) to have a policy that determines the conditions / criteria / thresholds when to leave the constellation, e.g., when the measured distance between the UE and one or more other UEs in the constellation exceeds a maximum distance, when the measured distance between the UE and one or more UEs in another constellation falls below a minimum distance, when the UE discovers (via the sidelink) a minimum number of UEs of another constellation, when the measured signal strength / quality (on the sidelink or on the Uu interface) falls below a certain minimum signal strength / quality threshold, when the number of discoverable devices (e.g., via the sidelink) falls below a minimum number, or when the battery falls below a certain level, etc. If the UE determines that it meets one or more of the above mentioned criteria / thresholds configured by the policy, it may either notify the management entity that it is leaving the constellation (whereby the UE indicates the constellation identifier in the notification message), request the management entity to leave the constellation (whereby the UE indicates the constellation identifier in the request message and / or includes information about the UE's current state (e.g., the UE's current location, the UE's current distance from one or more UEs in the constellation, the number of discovered devices (possibly including their identities), which thresholds have been exceeded, etc.), request to join another constellation (whereby the UE indicates in the request via the sidelink the discovered constellation identifier or a set of discovered UE identifiers), or inform other UEs in the UE's current ranging constellation via the sidelink that the UE is leaving the constellation.The management entity, in response to the request to leave the constellation or to join another constellation, sends a message containing confirmation or non-confirmation for the UE to leave the constellation or for the UE to join another constellation, configures the UE accordingly, and / or updates other UEs in the ranging constellation about the removed UE (e.g., by sending a new configuration).

[0138] 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 when to leave the constellation, perform a series of ranging measurements with one or more UEs of the ranging constellation or one or more UEs of another ranging constellation, perform discovery (via sidelink) of ranging capable devices, 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 exceeds a certain threshold and / or whether the number of discovered UEs exceeds a certain minimum value or is below a certain threshold, and based on this determination, leave the ranging constellation or join another ranging constellation.

[0139] Therefore, a device and a corresponding method are proposed, the device comprising a communication unit, a processor unit and a memory coupled to the processor, the memory comprising: storing a set of policies for determining conditions / criteria / thresholds when the device should leave the constellation (the conditions being received or stored prior to operation); the device performing a series of ranging measurements with one or more UEs of the ranging constellation or one or more UEs of another ranging constellation, performing discovery (e.g., via a sidelink) of ranging capable devices and / or performing measurements on one or more RF signals received via the sidelink or Uu interface; the device determining whether the ranging quality meets a criterion (e.g., whether the measured distance is below or exceeds a certain threshold and / or whether the number of discovered UEs exceeds a certain minimum value or is below a certain threshold) and leaving the ranging constellation or joining another ranging constellation based on this determination; The method includes instructions for executing the method.

[0140] Before self-configuration, the anchor UE informs the lead anchor UE and / or the management entity of its self-configuration and receives approval from them. The anchor UE makes this decision to stop working as an anchor UE based on a policy configured in the anchor UE by the lead anchor UE or by the management entity.

[0141] In a further embodiment related to automatically configuring a UE as an anchor UE 14, which may be combined with any other embodiment or implemented independently, the device UE 10 determines whether it has detected only a small number of positioning reference signals from the network access device 20 (e.g., gNB) or other anchor UE 14, or whether 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 decides to configure itself as an anchor UE 14 and start transmitting positioning / ranging reference signals. It is noted that the device UE 10 is configured by a management entity to have the capability to be allowed to configure itself as an anchor UE 14. This decision is based on a policy deployed by the management entity.

[0142] In other words, a device and method are provided in which the device UE 10 is configured to support ranging and further configured to store or receive (e.g., from a management entity) a set of policies / criteria based on which the device UE 10 can act as an anchor UE, perform a series of measurements on received RF signals, based on which the device UE 10 can identify or obtain its location, based on which the device UE 10 can determine based on the set of policies / criteria whether the number of positioning reference signals from the network access device 20 or other anchor UEs 14 or the RSRP of such reference signals is below a predetermined threshold, based on which the device UE 10 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 start a procedure to request to become an anchor UE 14 and / or to be configured as an anchor UE 14.

[0143] Switching to a local location / ranging service proxy In another embodiment, which may be combined with any other embodiment or implemented independently, the device UE 10 may determine (when and how) to obtain its location coordinates from a location service or from a ranging service based on ranging measurements, and one or more UEs in the ranging constellation 50 may act as a proxy for the location service and / or ranging service, e.g., in a given geographical area, by supporting a similar protocol (e.g., LPP or NRPPa) and (a subset of) the functionality provided by the location service or ranging service (e.g., determining distance / angle / position based on location / ranging measurements, providing location / coordinates in a reference coordinate system based on a set of distance, angle, and / or other related location information, etc.). The device UE 10 automatically turns off the use of location services provided by the core network / access device (e.g., terminates the connection to the LMF 34) when the device UE 10 discovers that the ranging constellation 50 of a ranging-capable anchor UE 14 is providing location coordinates, operating a location / ranging service, and / or acting as a proxy for nearby location / ranging services, when the device UE 10 determines that the access device has insufficient signal coverage in a given geographical area (which prevents proper / efficient use of location services), when the device UE 10 enters a particular tracking area or comes close to a particular access device, and / or when the device UE 10 meets a set of conditions defined by a preconfigured policy (e.g., when the device UE 10 can discover a certain minimum number of anchor UEs), and / or when the device UE 10 receives an explicit signal from an anchor UE, a location / ranging service, or a management entity (e.g., using one or more argument fields of a Mobile Terminated Location Request (MT-LR)).The device 10 requests from the LMF or other management entity permission to turn off the use of location services provided by the core network / access device, permission to use a location information / ranging service proxy (e.g., operated by a ranging capable anchor UE), and / or permission to perform ranging measurements for a given task, in a given context (e.g., in coverage, out of coverage, partial coverage) and / or for a given period of time, and based on this, an instruction (e.g., an acknowledgement) is provided to the device 10 and / or a policy (e.g., including conditions for determining when, where, and / or in what context the device is allowed to perform one or more of these operations) is downloaded to the device 10.

[0144] FIG. 8 illustrates an exemplary conceptual architecture according to an embodiment, whereby one or more anchor UEs act as a proxy for location / ranging services by supporting a subset of LMF capabilities 710 (e.g., ability to collect ranging / location measurements, ability to calculate the position of the device UE 10 or anchor UE 14, or ability to share the position with other entities (including the device UE 10 or anchor UE 14)). The anchor UE announces / provides information regarding its ability to act as a proxy for location / ranging services to the device UE 10 via sidelink / PC5 (e.g., during discovery) 701. The device UE 10 also provides a request / filter in its discovery request message via 701 specifically to discover only those anchor UEs capable of acting as proxies for location / ranging services. When multiple anchor UEs cooperate, e.g. as part of a constellation, it is not necessary for all anchor UEs to support such a subset of LMF capabilities. Other anchor UEs provide their measurement reports (e.g., ranging / location measurements) or distance / angle measurements to an anchor UE supporting a subset of LMF capabilities 710 via sidelink / PC5 702 (e.g., via a direct connection). Similarly, device UE 10 needs to provide its measurement reports (e.g., ranging / location measurements) or distance / angle measurements to an anchor UE supporting a subset of LMF capabilities. That anchor UE then calculates the location of device UE 10 and provides that location to device UE 10 via 701. In this way, device UE 10 can be located even if one or more anchor UEs are outside the coverage of access device 20. In FIG. 8, the coverage area of ​​access device 20 is illustrated as 720.An anchor UE within the coverage 720 of the access device 20 provides a local proxy using a subset of the LMF functionality 710, but switches off (part of) its local proxy functionality and interacts instead with the LMF in the core network, so that the anchor UE forwards messages / information from out-of-coverage devices UE 10 or anchor UE 14 to the LMF in the core network and vice versa. For this purpose, the anchor UE performs (a subset of) ProSe relay functionality and / or provides a gateway functionality for repackaging or converting incoming LPP messages coming from the AMF or from a management entity via TCP / IP into PC5 / sidelink messages (e.g. PC5 signaling messages with LPP payload) and vice versa. By acting as a gateway or ProSe relay, the anchor UE also provides indirect communication between other core network functions, such as an Authentication Server Function (AUSF) or a ProSe Key Management Function, for example, to forward a Mobile Originated Location Request (MO-LR) (including ranging related requests and / or information such as information about discovered anchor UEs or ranging constellations) from the device UE 10 to the AMF / GMLC / LMF, or to forward a Mobile Terminated Location Request (MT-LR) (including ranging related requests and / or information such as information about ranging constellations or ranging configuration information) from the AMF / GMLC / LMF to the device UE 10, so that the device UE 10 can exchange authentication and authorization information with the core network to verify whether the device UE 10 and / or anchor UE 14 are authorized to be involved in ranging of the device UE 10.

[0145] In further embodiments, which may be combined with any other embodiment or implemented independently, the device UE 10 may be self-configured or configured by a management entity to use ranging services within a given geographic area (e.g., inside a building) and location services outside the given geographic area (e.g., outside a building). To convert the ranging measurements into geographic or relative location coordinates, the ranging measurements are transmitted to the RMF 36 and / or LMF 34 and / or another location / ranging service, or a proxy thereof. The measurements are transmitted by the device UE 10, 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 are transmitted separately or combined and forwarded in a single report to the RMF 36 and / or LMF 34, or another location and / or ranging service, or a proxy thereof. For this purpose, the involved UE transmits measurements and / or estimated distances / angles between the involved UE 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 also acts as a proxy for the RMF, LMF, or other location or ranging services. In this case, the in-coverage UE transmits measurements or reports. If the entire constellation including the head anchor UE is out of coverage, the head anchor UE acts as a proxy for certain functions (e.g., a subset of functions) of the RMF and / or LMF or other location and / or ranging services. These functions include converting distance, time, and / or angle measurements into location coordinates, calibrating ranging measurements, temporarily storing measurements until the communication link with the access device is restored, etc.

[0146] Alternatively or additionally, the ranging measurements may be securely shared with an application function 40 (e.g., a third party application) via the NEF 38 by a ranging service, location service, RMF 36 or LMF 34 to calculate location coordinates of the device UE 10 based on approval by the device user.

[0147] In one embodiment related to switching to ranging services or ranging-based positioning services, the management entity can track locations where there are a sufficient number of ranging capable devices (e.g., configured to have a current location or have active location services) that together form a ranging-assisting constellation (e.g., ranging constellation 50) and can act as a proxy for location services in a given geographical area. The management entity uses this information to declare that the set of ranging capable devices form the ranging constellation 50 and / or to configure the devices (e.g., anchor UE 14) accordingly with the required parameters (as described in other embodiments). The management entity also configures 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 also includes information (e.g., in the form of policies) that associates the use of ranging services with locations / geographical area information / tracking areas / registration areas / cell IDs / synchronization signal block (SSB) indexes. The device UE 10 configures itself or is configured by a management entity to use ranging services in a given geographical area (e.g., based on (discovered / configured) information about one or more ranging constellations in the area) once it enters this geographical area. For this purpose, the device UE 10 uses 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 uses tracking area information / cell ID / SSB information received from access devices, relay devices, or discovered ranging capable devices and correlates this with the policy information to determine whether to enable ranging and / or which constellation and / or which anchor UE 14 to use.In one example, a management entity announces the presence and type of ranging or ranging-based location services in a given geographical area by requesting wireless access devices to include ranging information in an SIB, e.g., SIB1, broadcast by wireless access devices in the area. The wireless access devices broadcast the presence of ranging or ranging-based location services in the area by broadcasting such a SIB. Upon receiving the SIB, the device UE 10 recognizes the presence of ranging services and subsequently activates a sidelink to access or provide ranging-based location services.

[0148] In one embodiment, the device UE 10 is configured with a list of approved constellation identifiers and / or anchor UEs 14 that the device UE 10 can select for ranging and / or to which the device UE 10 can connect to initiate ranging, and possibly credentials that allow secure communication setup with each of the devices of the constellation, i.e., the anchor UE 14. This list is prioritized. Alternatively or additionally, the device UE 10 is configured to determine whether the device UE 10 should switch on ranging or start a ranging session, or to decide which constellation / set of anchor UEs to select / connect to for ranging, using a policy that specifies a minimum number of anchor UEs 14 that can be found in a constellation and / or in the vicinity of the device UE 10 and / or requirements regarding the capabilities and / or characteristics of the anchor UEs 14 (their (relative) movement being below / within a certain threshold, minimum / maximum distance from the device UE 10, signal strength thresholds, geographical area information, tracking area or cell information, PLMN information, whether they are within range of a network and / or whether they can or are connected to an LMF, etc.).

[0149] The anchor UE 14 exposes these capabilities and / or characteristics as part of a discovery message, capability exchange message, and / or other message for setting up or conducting a ranging / sidelink positioning session.

[0150] Additionally or alternatively, device UE10 may use such policies, capabilities and / or characteristics of the anchor UE to determine whether to use an LMF or a proxy of an LMF to calculate its location, what type of ranging procedure to initiate, what location request or other ranging session initiation message to issue, and / or what parameters / values ​​to include in a location request, ranging session initiation message, or as part of a ranging procedure.

[0151] The device UE 10 also uses its estimated location based on other means (e.g., GPS, Wi-Fi, or dead reckoning-based trajectory interpolation based on, for example, an internal accelerometer) to determine whether to use ranging services. Additionally or alternatively, the device UE 10 determines whether its location is sufficiently stable (e.g., using a certain allowable deviation threshold and / or varying within a sufficiently small (geographical) area, whereby motion is detected using sensors such as inertial sensors), whether the UE is moving at a fixed speed or at a speed that varies between a minimum and a maximum deviation threshold, whether the signal quality / strength of the positioning / ranging reference signal or the signal from the access device measured by the UE exceeds a certain minimum threshold, whether the Doppler shift / hysteresis (possibly indicated as a signal strength / quality threshold plus a scaling factor expressed in dB, whereby the scaling factor is different for different (relative) speeds) measured by the UE is within a certain threshold, whether the UE is within the coverage of a base station or connected to a certain network (e.g., Home PLMN). Based on one or more of these stability criteria (eg, as determined by a set of policies), the device UE determines whether to use the ranging service.

[0152] Once the device UE 10 determines to use the ranging service, it switches on discovery of other ranging capable UEs in its vicinity and / or connects (directly via Uu or via an intermediate device) to a ranging or location service provided by the network (e.g., provided or managed by the LMF 34 or RMF 36) for further instruction / configuration to the device UE 10. Alternatively, discovery of other ranging capable UEs is always switched on and the decision to use ranging can be based on information discovered from other ranging capable UEs (e.g., whether the discovered UE is an anchor UE or not, or based on (discovered / configured) information regarding one or more ranging constellations in the area, e.g., constellation identification information discovered via one of the ranging capable UEs, or based on discovering the presence of one or more UEs that make up the ranging / positioning constellation).

[0153] The UE 10 continues to use other existing positioning services.

[0154] Similarly, the anchor UE 14 is configured by a management entity or by the anchor UE 14 itself to switch on the ranging / ranging service (e.g., start sending and / or receiving discovery messages and / or start a ranging session) when it enters a geographical area or when the device UE 10 enters the area. It should be noted that every time the device UE 10 or anchor UE 14 enters a new area or comes in the vicinity of a new ranging constellation, it needs to request or be granted a new / new authentication and / or obtain a new / new 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 before or when joining a new ranging constellation.

[0155] In a related embodiment, the management entity is configured to automatically reconfigure the device UE 10 to connect to location services to obtain location coordinates when the device UE 10 leaves a given geographical area. The device UE 10 also reconfigures itself (e.g., based on a policy that associates the use of positioning services based on location / geographical area information / tracking area / registration area / cell ID / synchronization signal block (SSB) index).

[0156] Alternatively, the management entity automatically turns on or off ranging and location services depending on the last known location of the device UE 10.

[0157] When the device UE 10 discovers a constellation of nearby ranging capable UEs (e.g., ranging constellation 50) that can provide location coordinates by converting ranging measurements into location coordinates either directly as a result of ranging measurements or via a location service known to the constellation of ranging capable UEs, the device UE 10 automatically turns off location services (e.g., terminates the connection to LMF 34) itself.

[0158] In another / independent embodiment related to switching to ranging services or ranging-based positioning services, the device UE 10 may automatically turn on ranging services to search for nearby ranging-capable anchor UE 14 and / or constellations (e.g., ranging constellation 50) upon temporary disconnection from the LMF 34 or other location services provided by the core network, e.g., when out of range. For this purpose, the device UE 10 is configured to do so using a policy that determines the conditions, e.g., 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 conditions to switch on or off the use of ranging and / or positioning services.

[0159] In a related embodiment, which may be combined with other embodiments or used independently, the device UE 10 is not aware of the coverage situation of one or more of the anchor devices 14, the coverage situation has changed or is changing at the time when the ranging operation has just been started or is in progress, or out-of-coverage ranging operations are allowed to be performed (e.g., using distributed localization using a local proxy of the LMF) as well as centralized location (e.g., using the LMF / RMF of the core network via a direct Uu connection or via a UE-to-NW relay operated by the anchor UE) in in-coverage and partial coverage situations. In such a case, the device UE 10 performs an operation mode that is not a mode expected or desired by the anchor device 14 or the core network, or performs an operation mode different from the operation mode selected by the anchor device 14. Therefore, the device UE 10 includes a flag in a message (e.g., a direct communication request message) to one or more anchor devices 14 indicating the solution selected by the device UE 10 (e.g., out-of-coverage solution). When the one or more anchor devices 14 receive this message, they must check (based on the policy received when in coverage) whether the connection environment is out of coverage (e.g., whether one or more anchor devices 14 are actually out of coverage), whether an out-of-coverage solution is applicable, or whether, for example, a partial coverage solution is applicable (if one or more of the anchor devices can connect to the core network / LMF). If the policy of the one or more anchor devices 14 determines that there is a solution mismatch, for example, if the out-of-coverage solution is not allowed at the moment because one or more anchor devices 14 are in coverage, the one or more anchor devices 14 will not respond to the message or will send a response message indicating that the solution requested by the device UE 10 is not allowed / accepted by the anchor device 14. In principle, the anchor UE will take one of the following alternative steps: - not sending a message to the device UE 10 (eg ignoring it or continuing with the selected solution) or sending a message including a field indicating its coverage situation. - Sending a message to the device UE 10 to continue with the selected solution. - Send a message to the device UE 10 that the selected solution is not viable, this message containing information about another solution that the device UE 10 should choose from. - sending a message to the management entity requesting permission to proceed with the selected solution, which then informs the device UE 10 of the decision;

[0160] It should be noted that it is important that all UEs involved in ranging / sidelink positioning operations agree to use the same solution, since the selected solution (e.g. out-of-coverage, partial coverage or in-coverage solution) usually also determines which authentication procedure is performed and / or which security parameters (e.g. password, encryption key) are used. Therefore, it is advantageous if the verification of the type and parameters of the solution used is performed before the key establishment and authentication phase. In particular, it is advantageous if the verification of source UE authorization (step 4 of solution #4 of TR 33.740) is performed before the direct authentication and key establishment procedure (step 3 of solution #4 of TR 33.740). In this case, it is advantageous since the risk of denial of service is reduced.

[0161] It should also be noted that the solution indication in the request message sent by the device UE 10 may not be an explicit flag, but an implicit flag by sending one or more parameters specific to a particular solution. For example, if the request message includes an authorization token used during out-of-coverage operation, it will be clear to the anchor UE 14 that the device UE 10 has selected the out-of-coverage solution.

[0162] Furthermore, it should be noted that negotiation regarding the type of solution / protocol or parameters to be used (in-coverage or out-of-coverage) is negotiated, signaled, or verified during the initial discovery phase.

[0163] REQUIREMENTS FOR DISCOVERY AND USE OF RANGING CONSTELLATIONS In one embodiment, an anchor UE providing ranging and / or location services (e.g., ranging-based positioning services or proxies thereof) provides ProSe / V2X / D2D services to access such ranging and / or location services over a sidelink, e.g., to be able to obtain / provide location information or initiate ranging. Such ProSe services are announced through sidelink discovery with a specific ProSe / V2X / D2D service identifier or application code, after which other UEs set up connections to such services over sidelink and use such services. The LMF 34, RMF 36, other ranging and / or location services, or other management entities provide credentials that enable and / or can be used to secure discovery and / or message exchanges between the ranging-enabled device UE 10 and the anchor UE 40.

[0164] In a further embodiment, the device UE 10 is configured to obtain or request its location coordinates based on ranging measurements from one or more of the anchor UEs 14 of the ranging constellation 50. The anchor UE 14 transmits discovery messages at configurable time intervals that announce ranging reference signals (e.g., ranging reference signals detected by nearby devices UE 10 based on their frequency, timing, signal characteristics / type, waveform, bandwidth, configured resources), announce ranging-based positioning (combining ranging and location service capabilities) as a proximity service, announce support for ranging / location services and / or other ranging / position capabilities, and / or provide information about its (last known) location, known to ranging services and / or configured (e.g., by a management entity) on UEs involved in the particular ranging constellation 50 to which the anchor UE 14 belongs. Thereby, the device UE 10 identifies the announcement / discovery message, checks its integrity, determines the arrival time of the announcement / discovery message, extracts from the message, for example, timing information (e.g., the transmission time of the announcement / discovery message contained in the message, the processing time of the message to which this message is responded (e.g., t3-t2 for FTM), the reception interval of the message to which this message is responded, clock synchronization information) and calculates the distance between the device UE 10 and one or more of the anchor UEs 14 of the ranging constellation. Furthermore, the device UE 10 calculates a bounded area that approximates its location coordinates, for example based on one or more distances obtained 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 receives a list of approved anchor UE 14 in its vicinity via the RMF 36, the LMF 34 or a management entity, and when it approaches an approved anchor UE 14 within its ranging distance, e.g. after the device UE 10 discovers such an approved anchor UE 14, connects to it and / or requests the use of a ranging / location service or service proxy provided by such anchor UE, the device UE 10 obtains 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, the LMF 34 or other location services of the core network 30 (e.g., a network controller device). In this case, the anchor UE 14 uses a ranging procedure / service to measure the distance and / or angle between itself and the device UE 10 and converts the distance into location coordinates based on its current location coordinates locally on the device. Alternatively, the device UE 10 uses a ranging procedure / service to measure the distance and / or angle and forwards it to the anchor UE 14 requesting it to convert the measured distance into geographic coordinates.

[0165] In another embodiment, the anchor UE 14 provides its geographic coordinates to the device UE 10, which can use them after measuring the distance and / or angle between itself and the anchor UE 14. The transmission of the geographic coordinates of the anchor UE 14 should be done in a secure manner in terms of integrity and / or confidentiality, and thus the anchor UE provides its coordinates only after a secure communication channel has been established between the device UE 10 and the anchor UE 14, and / or transmits the geographic coordinates protected by a key that only the device UE 10 or a set of authorized device UE 10 can decrypt this information and / or the device UE 10 or a set of authorized device UE 10 can verify the integrity of the information (by a message integrity code or a digital signature).

[0166] In one embodiment, instead of sending 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 sends (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)) an identifier (e.g., a location identifier pre-configured / allocated to the anchor UE by a location service / database, or self-allocated), possibly along with an identifier or address of the location service / database, to the device UE 10 or other anchor UE, which the device UE 10 or other anchor UE receiving can use this identifier to obtain the location coordinates of the anchor UE through 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 connects). To enable this, the anchor UE (e.g., configured / authorized by a user or a management entity), an anchor UE on behalf of a management entity, or a management entity on behalf of an anchor UE, provides permission to obtain the location of the anchor UE by doing one (or more) of the following: - granting authorization by providing the device UE 10 or other anchor UE with authorization credentials (e.g. authorization token), which can be used to authenticate / verify that the authorization (i.e. the authorization provided by the connected anchor UE 14) is genuine, for example by performing an authentication procedure with the respective anchor UE 14, or by verifying whether the credentials match or are securely associated with credentials of the anchor UE 14 previously stored in the device UE 10, the other anchor UE, the LMF 34, RMF 36 or other location and / or ranging service or their proxies, other management entities, or core network functions (e.g. UDM / AUSF) to which the device UE 10 or other anchor UE can connect. The anchor UE registers the given consent with the particular device UE 10 or other anchor UE, or provides a copy of the given authorization credentials (e.g., authorization token) for the device UE 10 or other anchor UE to the LMF 34, RMF 36 or other location and / or ranging service or their proxy, other management entity, or other core network function (e.g., UDM / AUSF). The device UE 10 or other anchor UE can include the provided authorization credentials / token in a message request to the LMF 34, RMF 36 or other location and / or ranging service or their proxy, other management entity, or anchor UE 14, which then verifies that the authorization credentials / token are authentic and, if so, provides the location of the anchor UE 14 to the device UE 10 or other anchor UE. - granting authorization by providing an authorization message / credentials to the respective LMF 34, RMF 36 or other location or ranging service or their proxy, other management entity or location database, so that the message / credentials can be verified as originating from the respective anchor UE, e.g. by performing an authentication procedure at the respective anchor UE 14, or by verifying whether the credentials match or are securely associated with credentials of the anchor UE 14 previously stored in the LMF 34, RMF 36 or other location and / or ranging service or their proxy, other management entity or core network function (e.g. UDM / AUSF). Such an authorization message contains several fields / payloads containing information about the consent given, e.g. validity period, for which UE the consent was given (e.g. set of identities), information about credentials or tokens that must be provided by the given UE before the anchor UE location can be given. The authorization message is sent by the anchor UE 10 upon registration with the network, upon receipt of a ranging request (e.g., when the device UE 10 connects to the anchor UE 14 and requests to use the ranging service), or, for example, when the device UE 10 connects to the LMF 34, RMF 36 or other location service and / or ranging service or their proxy, or other management entity for the first time, or in response to the LMF 34, RMF 36 or other location service and / or ranging service or their proxy, or other management entity sending a message to the anchor UE requesting permission to share its location information with the device UE 10.If a group / domain credential, authorization token, closed access group, NPN, or (private) network slice is associated with a ranging constellation that is used to secure communication between UEs of the ranging constellation and / or to restrict communication only between UEs that belong to that group / domain / closed access group / NPN / slice, the anchor UE only needs to provide consent once for all UEs of the ranging constellation (e.g., by including the ranging constellation id, group / domain credential, and / or closed access group, NPN, or (private) network slice information with which the consent is associated in a message that the anchor UE sends to the LMF34, RMF36, or other location and / or ranging service or their proxy, or other management entity). For example, this is done during a message exchange when the anchor UE joins the ranging constellation. Consent is also provided by an application that manages the ranging constellation and / or the involved UEs (through the NEF), for example, by providing it implicitly or explicitly in the ranging constellation configuration information it sends to the LMF or other management entity. The consent is also stored in the UDM or GMLC (typically in the home network of the target UE) and is verified, for example, by the AMF or other core network function. - By providing consent in the subscription (e.g. UDM) or by providing permission for this by providing consent through the Network Publishing Function (NEF) (e.g. by the application managing the respective anchor UE). Note that the consent provided in the subscription or through the NEF is configured per ranging constellation or per group / domain / closed access group / NPN / (private) network slice associated with the ranging constellation.

[0167] In a related embodiment, since sharing the location of the anchor UE is privacy sensitive, information regarding whether the anchor UE is willing to share its location with other ranging capable UEs is added to the privacy profile for ranging (e.g., by extending the privacy profile for location services as described in 3GPP TS 23.273). This information includes whether the anchor UE (also called a located UE if its location is known or identifiable) supports sharing its location publicly, or only with (authorized) target UEs, only with other (authorized) reference UEs, only with target or reference UEs that are part of the same constellation or share the same group ID / credentials, and / or only with the LMF34, RMF36 or other location and / or ranging services or their proxies, other management entities, or core network functions (e.g., UDM / AUSF). The anchor UE's privacy profile or information thereof (e.g., profile identifier, profile type, summary of certain aspects of such profile, subsets of values ​​(possibly in different data formats)) is shared with other UEs of the ranging constellation (e.g., by the anchor UE itself, indirectly via the LMF34, RMF36 or other location and / or ranging services, or proxies thereof), e.g., during discovery, initial capability exchange, or session / connection setup. Additionally or alternatively, the anchor UE indicates its support for sharing its location using a location privacy field containing several values ​​of various options (e.g., setting a specific bit if sharing with the target UE is supported), e.g., in a message, capability exchange message, or session / connection setup message.Additionally or alternatively, the anchor UE may indirectly indicate that it supports sharing of its location by indicating in the discovery, capability exchange, or session / connection setup messages a list of supported ranging and / or positioning methods (including information on which entity performs measurements and / or calculates the position, including information on support of specific location requests (e.g. MO-LR), and including information on support of specific positioning methods (e.g. RTT, TDOA)), such that the anchor UE includes the supported ranging and / or positioning methods if they match the anchor UE's privacy profile, and excludes them if they do not match the anchor UE's privacy profile. For example, if the anchor UE does not support sharing of its location with the target UE, the anchor UE may indicate that it supports only "Network-Assisted SL Positioning" and / or only MT-LR location requests. A target UE or other anchor UE that discovers / receives information about the anchor UE's support for location sharing uses it to select this or another anchor UE and initiate ranging and / or ranging / sidelink positioning procedures or issue a location request that matches the anchor UE's support for location sharing and is supported in a given coverage situation. This depends on pre-configured policies or policies or instructions provided by the LMF 34, RMF 36 or other location and / or ranging services or their proxies or other management entities (e.g. as part of a location request message such as MT-LR) to determine criteria on how to handle the various options. For example, if the anchor UE does not support location sharing with the target UE but only supports location sharing with the LMF, the target UE will initiate a direct connection (via Uu) or an indirect connection (e.g. via relay) with the LMF and request the LMF to calculate the target UE's location instead of the target UE calculating the target UE's location itself.The target UE provides information regarding which ranging / sidelink positioning procedure the target UE selected and / or which anchor UE it selected and / or which entity performed the ranging measurements and / or distance / angle / position calculations (e.g., target UE, anchor UE, LMF34, RMF36 or other location and / or ranging service or their proxies, or other management entities) to the entity that issued a location request to the target UE and / or the entity that requested the results of the ranging / sidelink positioning procedure (e.g., the resulting location of the target UE).

[0168] In a further embodiment, the device UE 10 calculates its location coordinates based on ranging reference signals obtained from one or more anchor UEs 14 via a sidelink channel (e.g., through sidelink discovery messages or other signals transmitted using sidelink resources) and location information of the one or more anchor UEs 14. For this purpose, the device UE 10 and the one or more anchor UEs 14 exchange messages for initiating a ranging session. One or more of these messages include a ranging session ID (used by all UEs involved in participating in the ranging session), include a ranging constellation identification, and / or include a ranging reference signal. The ranging reference signal includes (encoded) information regarding the type of reference signal, UE identification, ranging session ID, ranging constellation identification, constellation identification, qualification information, nonce, timing information, and / or distance / angle / location information.

[0169] In a further embodiment, if the device UE 10 wants to start ranging with two or more anchor UEs, the device UE 10 indicates the number of anchor UEs, the set of anchor UE identifiers, and / or the constellation identifier as part of a message for starting 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 are sent as multicast / broadcast messages to all involved anchor UEs, which based on this message start ranging with the device UE 10 and / or send respective configuration parameters for ranging to the device UE 10, or these messages are sent via unicast messages to one of the anchor UEs (e.g., the head anchor UE), which based on this message sends messages to other anchor UEs in or near the constellation to invite them to be part of the ranging session, to start ranging with the device UE 10, and / or to send them respective configuration parameters for ranging.

[0170] In further embodiments, location coordinates of the anchor UE 14 are exchanged with the device UE 10 via a sidelink channel, and the position calculation is performed after the device UE 10 achieves clock time synchronization (simultaneously) with those anchor UE 14 and / or is connected 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 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, if the device UE 10 or anchor UE 14 has multiple antennas, the angle is determined. Assuming that the device UE 10 and one or more anchor UEs 14 are in the same horizontal plane (i.e., at a similar altitude) and the distance and / or angle between the anchor UEs 14 are known or computable (e.g., calculated based on the geographic coordinates of the anchor UE 14 and / or distance / angle measurements performed between two or more anchor UEs 14, the results of which are shared with the device UE 10 and / or a ranging / location service), the position of the device UE 10 can be calculated based on trilateration and / or triangulation by using the distance measurements between the device UE 10 and at least two anchor UEs 14 (as well as information about the known or calculated distances and / or angles between the anchor UEs and / or the location coordinates of the anchor UE 14) or the distance and angle measurements between the device UE 10 and at least one anchor UE 14 (as well as information about the known or calculated distances and / or angles between the anchor UEs and / or the location coordinates of the anchor UE 14).

[0171] To address possible altitude differences between UEs in a ranging constellation, the device UE 10 requires distance and / or angle measurements using additional anchor UEs as additional references.

[0172] Using Non-RF Sensors According to one embodiment, which may be combined with any other embodiment or implemented independently, the device UE 10 has 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 the altitude of the anchor UE 14 (e.g. sea level or a particular horizontal plane) determined by the barometric pressure sensor or GNSS, the anchor UE 14 transmits information about its altitude (e.g. in the form of a Z-axis coordinate (e.g. 3D coordinate or Z-axis value), meters from sea level or a particular horizontal plane, or as a barometric pressure value) to the device UE 10, which uses this information in calculating the possible difference in altitude between the device UE 10 and the respective anchor UE 14. Alternatively, the device UE 10 shares information about its altitude with the anchor UE 14 and / or the ranging / location service to calculate the altitude difference. Once the altitude difference is calculated / estimated, this value is used in a subsequent (3D) location coordinate calculation to estimate the location of the device UE 10, including the altitude of the device UE 10, taking into account the determined altitude difference between the device UE and one or more anchor UEs 14. Similarly, the position calculation may also 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 about the angle of the target mobile device (e.g., UAV, etc.), a sonar sensor that provides information about 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 for calculating a position of a target mobile device (e.g., device 10) (e.g., an anchor UE 14 providing ranging / location services or RMF 36 or LMF 34) is adapted to calculate location coordinates of the target mobile device based on ranging reference signals obtained from one or more anchor devices of a ranging constellation via a sidelink channel and sensing information collected by the target mobile device or anchor UE and provided as input to the apparatus for calculating a position of the target mobile device.Additionally or independently, if the device UE10 or anchor UE has means for determining x-axis or y-axis coordinate values ​​(e.g., relative to a preconfigured reference plane and / or coordinate system), it transmits such values ​​to the apparatus to calculate the position of the target mobile device.

[0173] In one embodiment, device UE 10 requiring ranging over sidelink / PC5 and supporting anchor UE 14 are configured to perform ranging with 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). Specifically, device UE 10 or anchor UE 14 can act as an ultrasonic or audio source, typically using a speaker, or as an ultrasonic or audio receiver, typically using a microphone.

[0174] In one embodiment related to the previous embodiment, device UE 10 requiring ranging over the sidelink / PC5 interface and anchor UE 14 supporting ranging operation rely on "non-sidelink ranging reference signals" that are not exchanged over the sidelink / PC5 interface but whose parameters are configured or announced over the sidelink / PC5 interface. Specifically, "non-sidelink ranging reference signals" refer to ultrasound / audio signals, for example, generated by device UE 10 or anchor UE 14 and received by anchor UE 14 or device UE 10, respectively. Specifically, parameters of ultrasound / audio signals include frequency of ultrasound / audio signals, for example 40Khz, timing (start time) of ultrasound / audio signals, or identifiers, for example modulation of ultrasound / audio signals.

[0175] In a related embodiment, the device UE 10 acts as an announcing UE and transmits (e.g., sporadically or periodically) discovery messages that are received by the anchor UE 14 acting as a monitoring UE. The discovery messages transmitted by the device UE 10 include a timing or an identifier of the "non-sidelink ranging reference signal", e.g., a given delay with respect to the transmitted discovery message. The discovery messages also include the temperature / humidity measured by the device UE 10, since temperature / humidity are some factors that affect the speed of sound in air. At least one (monitoring) anchor UE 14 in the ranging constellation 50 receives the discovery messages, learns the parameters of the "non-sidelink ranging reference signal", and then measures the "non-sidelink ranging reference signal" to obtain ranging measurements by the device UE 10.

[0176] The use of such a "non-sidelink ranging reference signal", e.g. an ultrasound signal, may have multiple advantages including 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)s in the transmission of the discovery message. Assuming that the clock synchronization error is 1 / 3*10^(-6) and both the device UE 10 and the anchor UE 14 use a speed of sound of 340 m / s while the actual speed of sound is 339 m / s, the ranging result will be 9.97 m.

[0177] Licensed / Unlicensed Spectrum In one embodiment, which may be combined with any other embodiment or implemented independently, the device UE 10 or the anchor UE 14 also has a policy that determines whether it can / should use licensed or unlicensed spectrum for a particular location / geographical area information / tracking area / registration area / cell ID / synchronization signal block (SSB) index (also includes information about preferred frequencies / bands, bandwidths, etc.). An additional criterion, which is also part of the policy information, on whether it can / should use licensed or unlicensed spectrum is whether the device UE 10 and / or the anchor UE 14 is in or out of coverage of the access device. If both UEs are in coverage, then typically the use of licensed and unlicensed spectrum is allowed, and if both UEs are out of coverage, then typically only the use of unlicensed spectrum is allowed, taking into account that the mobile network operator wants to control the use of licensed spectrum. A particular 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 also changes if the UEs are moving. Therefore, it is important that the UEs involved in ranging can inform each other of their coverage status in advance (e.g., via a core network function), during discovery, during connection setup, during the initiation of the ranging session, and / or while performing the ranging procedure. The UE decides whether it is out of coverage or not based on some (preconfigured) thresholds 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) exposes its coverage status (e.g., whether UE1 is in coverage or not) as a field in a transmitted discovery message or synchronization signal such as a sidelink synchronization signal (e.g., through exposing some signal quality / strength value / level measured by UE1 (e.g., associated with a set of access devices 20) with a Boolean value indicating whether UE1 is in network coverage or not, or through exposing or not exposing cell ID information received from nearby access devices 20), or by transmitting a discovery response message or synchronization signal in a different (e.g., unlicensed) frequency band than the discovery request message or synchronization signal transmitted by another UE (UE2). If the receiving UE (UE2) receives a discovery message or synchronization signal indicating that the other UE (UE1) is out of coverage, UE2 is configured / requested / instructed to use unlicensed radio spectrum resources instead of licensed resources to set up a subsequent connection to initiate a ranging session or to perform ranging using a ranging reference signal. A UE receiving a discovery message or synchronization signal is pre-configured (e.g., through a policy) as to whether it can make an exception to connect to licensed resources instead if the UE receiving the discovery message or synchronization signal is itself within the coverage of the network. Such pre-configuration / policy also defines distance or area information indicating the maximum allowed displacement between the UE receiving the discovery message or synchronization signal and the UE transmitting the discovery message or synchronization signal, within which the use of licensed spectrum is permitted and outside which unlicensed spectrum must be used. A UE receiving a discovery message or synchronization signal is configured / required to limit the transmission power of subsequent signals it transmits in licensed spectrum to prevent the signals from traveling beyond the maximum allowed distance. If the receiving UE can locate itself within the pre-configured area information, the receiving UE is configured / required to limit the transmission power of subsequent signals it transmits in licensed spectrum to prevent the signals from traveling beyond the allowed area.Similarly, during subsequent message exchanges for connection setup, initiation of a ranging session, or performing ranging using a ranging reference signal, each UE transmits information about its coverage status using an attribute in one of those messages or as a separate message (e.g., a MAC Control Element concatenated in one of those messages). If a change in coverage status occurs during these procedures, the involved UEs need to switch the use of the frequency / band they use. For example, if the UE was initially communicating in a licensed band, the UE is configured / requested / instructed to switch to using an unlicensed band instead. For this purpose, a configuration change procedure needs to be performed, in which at least one UE informs the other UEs that it will 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 UE. Instead of performing a message exchange to determine a new frequency to use, the involved UEs are also configured with a default / fallback frequency to continue the procedure if the UE receives an update of the coverage status of the other UE. Alternatively, the involved UEs are also configured with a time interval during which they are exempt from switching frequency bands, for example for a certain number of seconds or until the ranging procedure is finished (e.g., a portion of the ranging reference signal, e.g., a certain burst). The UEs are also configured with a maximum distance, within which they are allowed to continue using licensed spectrum and outside of which they are required to use unlicensed spectrum. Using the ranging results obtained so far, the UEs determine that the distance is within the limits for continuing to use licensed spectrum or that they need to switch to unlicensed spectrum because the distance is outside the limits. In a related example, the device UE 10 is out of coverage and the anchor UE 14 is in coverage and knows its location or provides a location / ranging service proxy or has access to location / ranging services.The device UE 10 performs 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 receives a signal (e.g., a discovery message or other ranging reference signal) from the anchor UE 14 (which transmits such a signal from time to time on a pre-configured set of licensed / unlicensed radio spectrum resources) through which the device UE can determine the distance and / or angle (using one of the methods described above). Using the measured distance and / or angle, the device UE 10 determines a location estimate (either on the device UE 10 itself after receiving some information regarding the anchor UE's location, by using a location / ranging service proxy, or by accessing a location / ranging service (e.g., through a relay connection and / or by using the last known location of the device UE 10 or the anchor UE 14)) and determines based on this location estimate that the device UE 10 is located within a particular geographical area that 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, assume that a first device (FD) is out of coverage and a second device (SD) is in coverage. In this case, the FD transmits a sidelink synchronization signal (SSS) in the unlicensed spectrum and listens to the SSS in both the licensed and unlicensed spectrum. The SD receives the FD's SSS (indicating out of coverage) and informs the SD of its presence. The SD will do this using unlicensed spectrum and will either perform ranging in this spectrum or, based on policy, the SD receiving these SSS from the FD will inform the FD and then transmit the SSS in licensed spectrum so that the FD can connect to the licensed spectrum and use ranging.

[0178] speed estimation In one embodiment, when the device UE 10 discovers a ranging device within the ranging distance, it can measure the distance and angle with the ranging device (e.g., anchor UE 14) and continuously track these measurements and timing for all distances traveled by the device UE relative to the first measurement made by the device UE 10 with the discovered ranging device. While tracking the distance and angle measurements obtained from the ranging device along its moving trajectory, the device UE 10 periodically attempts to reacquire a connection to the LMF 34, RMF 36, or other location service provided by the core network or anchor UE, or to obtain new location coordinates from the ranging device. This allows the device UE 10 to estimate its relative speed and / or moving pattern / trajectory. If information regarding the absolute / geographical location, speed, and / or moving pattern / trajectory of each anchor UE 14 and / or whether each anchor UE 14 is stationary or not is transferred 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 is also calculated.

[0179] In one example, inertial sensors (such as, for example, an accelerometer and / or a gyroscope) provided on the device UE 10 may be used to assist ranging services for determining and tracking a movement trajectory.

[0180] Data from such inertial sensors is 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 services. The device UE 10 locally calculates a movement trajectory based on the distance and direction moved and combines this information with the last known location coordinates to determine the current coordinates of the device UE 10. Alternatively, the device UE 10 adds the inertial sensor-based calculated distance and direction information to a discovery 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 (which operates the ranging and / or location services) or the RMF 36 and / or LMF 34 (to which the inertial sensor-based distance / direction information is forwarded) receiving such a message can then calculate the current coordinates based on the inertial sensor measurements from the device UE 10. Distance and orientation calculated from inertial sensor measurements may also be used optionally and / or in addition to the ranging measurements, depending on other factors such as the error rate of ranging measurements in a given environment, as well as user intent and / or device capabilities.

[0181] Upon re-establishing a connection with the LMF 34 or other location service provided by the core network or anchor UE and obtaining current location coordinates, the device UE 10 automatically recalculates location coordinates based on the last known location coordinates and the distance and angle measurements obtained while the connection with the LMF or other location service was disconnected. Alternatively, upon re-establishing a connection with the LMF 34 or other location service provided by the core network or anchor UE, the device UE 10 transmits (e.g., to a nearby anchor UE 14 or other ranging-capable UE) the distance and angle measurements obtained while the connection with the LMF 34 or other location service was disconnected, and also transmits the last known location coordinates. This allows the LMF 34 or other location service to quickly determine the current location of the device UE 10.

[0182] It should be noted that the anchor UE 14 in the ranging constellation 50, while performing ranging operations with the device UE 10, may report the identity / ranging measurements of the device UE 10 to its ranging or location service, or to the LMF 34, RMF 36, or other location / ranging services provided by the core network, or their proxies provided by the anchor UE 14, so that location coordinates corresponding to the current location of the device UE 10 may be updated in the location registry.

[0183] Using FR1 / FR2 to determine line of sight In another embodiment, which may be combined with any other embodiment or implemented independently, the device UE 10 and the anchor UE transmit and / or exchange positioning signals and / or messages in different frequency bands, e.g., the frequency bands FR1 and FR2. Possibly, this transmission and / or exchange is done by using carrier aggregation (i.e., transmitting a ranging reference signal in two different bands simultaneously that is duplicated or split between the bands) or by using different bands intermittently. The term "positioning signal" as used in this specification and subsequent embodiments is used in the context of location services using an access device (e.g., the access device 20 using an infrastructure connection / Uu interface) and can also be used for ranging reference signals for determining the distance and / or angle between two devices (e.g., using a sidelink / PC5 interface).

[0184] For example, in a first step, the device UE 10 receives or transmits a message requesting / offering ranging services in the FR1 frequency band. In a second step, the device UE 10 receives or transmits positioning signals in both the FR1 and FR2 frequency bands. The device UE 10 uses the signal quality or distance measurement results of the message (e.g., ranging reference signal) transmitted in the FR1 frequency band to determine whether to transmit a signal in FR2 or not, to determine that the device UE 10 is sufficiently close to and / or has a line of sight (LoS) with another ranging capable UE. This determination is based on device capabilities or an indication received from the other ranging capable device, which allows the device to determine that the other ranging capable UE supports FR2. For this purpose, during discovery or connection setup between two ranging capable UEs, the supported and / or preferred frequencies / bands of the ranging capable UEs are published / exchanged. Similarly, the support of carrier aggregation and / or the bands supported in carrier aggregation are also published / exchanged. In a third step, the device UE10 or the anchor UE14 collects measurements of their positioning signals and optionally transmits the measurements to a management entity or ranging / location service for evaluation. In a fourth step, the device UE10, the anchor UE14, the management entity or the ranging / location service determines the LoS capability of the communication link based on the collected measurements. The positioning signals or messages serve, for example, to calculate round trip times. If the measurements are performed when exchanging positioning signals or messages in the FR1 band, the measurements may be successful even when there is no direct LoS, for example when the devices are separated by a house wall. However, if the measurements are performed when exchanging positioning signals or messages in the FR2 band, the measurements will be unreliable due to poor propagation of wireless messages in the FR2 band. Not all steps are always necessary and the steps may be performed in a different order.

[0185] Thus, based on these measurement results (especially if the measurements on FR1 were successful while the measurements on FR2 were not), it may be determined whether the device UE 10 and the anchor UE 14 are within line of sight of each other. Based on whether the device UE 10 and the anchor UE 14 are within line of sight of each other, the UE may decide to use only FR1 (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.

[0186] Alternatively, measurements made in the FR1 and FR2 bands may be analysed, for example by a management entity, to indicate whether the received power changes as expected when LoS is available.

[0187] The transmitting UE varies the transmit power of signals in different frequency bands (in accordance with the calibration information) in a manner such that the receiver is expected to measure similar and / or specific values ​​for signal strength / quality, and includes the transmit power information as part of the positioning signal and / or pre-exchanged messages (e.g., as part of the ranging session setup).

[0188] An alternative means for determining whether two UEs are within LoS range is to exchange positioning signals including subcarriers at both FR1 and FR2 frequencies. The measured signal strengths of the positioning signal subcarriers at FR1 and FR2 frequencies are then used to identify the LoS characteristics of the communication link. If the anchor UE and the UE are within LoS range, the positioning signal transmitted at the FR2 frequency is 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 lower signal quality (e.g., RSRQ) or not received at all compared to the received positioning signal transmitted at the lower FR1 frequency. For this purpose, the transmitting UE changes the transmission power of the signals at the different subcarriers (according to the calibration information) in such a manner that the receiver is expected to measure similar values ​​for signal strength / quality, and includes the transmission power information as part of the positioning signal and / or pre-exchanged messages (e.g., as part of the ranging session setup).

[0189] Centralized Localization In an embodiment related to centralized localization based on ranging measurements by the anchor UE node 14, the device UE 10 approaches an anchor UE 14 of a ranging constellation 50 and performs ranging measurements. Upon receiving a ranging request from the device UE 10, the anchor UE 14 informs the device UE 10 about the ranging constellation 50 via the LMF 34, RMF 36, or other location or ranging service, or via another communication channel. The device UE 10 can store the constellation information and, as long as the device UE 10 is in the vicinity of the ranging constellation 50, can determine based on the ranging measurements whether it wants to receive location coordinates from one or more of the anchor UEs 14 or other UEs 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 are part of a positioning constellation 60, whereby the location service (centrally) determines the location of the device UE 10. The device UE 10 connects to and / or receives information from the LMF 34, RMF 36, or other location or ranging services provided by the network, either directly over the Uu interface or via a relay connection (e.g., over a secure connection or exposed via a relay device discovery message) between the device UE 10, another UE, and an access device 20 that provides access to the LMF 34, RMF 36, or other location or ranging services. The anchor UE 14 or ranging capable device UE 10 acts as such a relay device (e.g., using the ProSe relay service) with respect to other UEs, e.g., other UEs that are part of a positioning constellation.A UE that is part of a ranging or positioning constellation is configured with specific identification information and parameters, e.g., relay service code and / or discovery credentials, that allow other UEs that are part of the constellation, other UEs in the vicinity, and / or other UEs capable of ranging and / or location services to access the LMF 34, RMF 36, or other location and / or ranging services via a ProSe relay connection based on the specific relay service code. The LMF 34, RMF 36, other ranging and / or location services, or other management entities provide credentials that can be used to enable and / or protect discovery and / or message exchanges between the ranging capable device UE 10 acting as a remote UE, the respective UE acting as a relay device, and the ranging / location services.

[0190] When the device UE 10 needs to obtain its location (e.g., geographic) coordinates, it initiates a ranging request via a ranging service with any anchor UE 14 of the ranging constellation 50, indicating that location coordinates are required. Upon receiving the request for location coordinates, (at least) one anchor UE 14 of the ranging constellation 50 performs ranging measurements and shares the ranging measurements, e.g., with the RMF 36 and / or the LMF 34, to obtain the geographic coordinates of the device UE 10 based on the ranging measurements between the device UE 10 and the anchor UE 14 of the ranging constellation 50. When more than one anchor UE 14 performs ranging measurements, the ranging measurements are combined into a single report (e.g., by a head anchor UE collecting ranging measurements from various anchor UEs and sending the combined ranging measurements to the LMF 34 or RMF 36). It should be noted that such a report can be generated by the device UE 10 since it performs ranging with each of the anchor UEs 14 if these anchor UEs 14 are explicitly involved in the ranging of the device UE 10 (e.g. by participating in the same ranging session). The report is sent, for example, directly to the RMF 36 and / or LMF 34 or indirectly via the (head) anchor UE 14. In a variant of the embodiment, the target or anchor UE sends the ranging measurements to the gNB as part of a measurement report, whereby the measurement report performed for ranging (e.g. which ranging reference signals to monitor and / or report) is configured through the measurement configuration included in the RRC reconfiguration or RRC resume message. The measurement report includes a flag / indicator indicating that this measurement report relates to sidelink related measurements, e.g. measurements on ranging reference signals. The measurement report includes information about which ranging reference signals the target or anchor UE has received or transmitted and / or the timing of the reception or transmission of the ranging reference signals.

[0191] As mentioned above, the anchor UE is also implicitly involved, for example by receiving information (e.g., reference signal characteristics / type, timing, or resource information) from the LMF or other management entity, which enables the anchor UE to monitor the ranging reference signal being transmitted by the device UE 10, even if the device UE 10 is not aware of this anchor UE or is not participating in the same ranging session.

[0192] It should be noted that the LMF 34 and / or RMF 36 requests the anchor UE 14 to provide its own known location coordinate information and / or antenna orientation information, if known, to the LMF 34 and / or RMF 36. The antenna orientation information is then used by the LMF 34 and / or RMF 36 to improve ranging methods, for example for customized beamforming, and improves the angle of arrival calculation between the anchor UE 14 and the device UE 10 for a given antenna orientation. Additionally, the LMF 34 and / or RMF 36 requests the 5GS infrastructure to evaluate the location and orientation of the anchor UE 14. This may include, for example, requesting the anchor UE 14 to 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, the 5GS infrastructure determines the orientation of the anchor UE 14 if the anchor UE 14 returns a beamforming configuration (e.g., transmit power, direction) when, for example, performing Reference Signal Time Difference (RSTD) and / or Reference Signal Received Power (RSRP) measurements with one or more different wireless access devices 20 (e.g., gNBs). In this case, the wireless access device 20 (e.g., gNB) performs beam sweeping during initial access or broadcast of SSBs or performs 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 transmits, for example, synchronization signals (SS) in multiple directions. The wireless access device measures the received power of different synchronization signals and combines the measurements to calculate the orientation of the anchor UE 14 according to the signals / responses that the wireless access device 20 (e.g., gNB) receives from the anchor UE 14 in different beam directions.As shown in FIG. 10, in another embodiment related to centralized localization, the LMF 34 (or RMF 36, or other management entity) is instructed / configured (e.g., by the GMLC 37 via the AMF 32 or directly by the AMF 32) to monitor the locations of a set of anchor UEs (e.g., for a given set of anchor UEs 14 in the ranging constellation 50, or for anchor UEs in a particular area based on area information such as (a set of) tracking areas, (a set of) gNB / cell identifiers, (a set of coordinates) associated with the ranging constellation 50) over a certain period of time based on, for example, periodic Mobile Termination Location Requests (MT-LR) 1001 issued by the GMLC 37 for the respective set of anchor UEs. The LMF configures a set of anchor UEs and / or the AMF (and / or the NG-RAN (not shown)) to periodically provide updated location information to the LMF (1003) and / or perform measurements and send ranging / location measurements to the LMF (1002) so that the LMF can determine new locations of the anchor UEs. The LMF stores the latest locations of all these anchor UEs in its own storage or requests another core network function (e.g., the GMLC 37 or the Unified Data Repository (UDR) 39) to store the location information of these UEs (1004). The location information of the anchor UEs is further updated each time the anchor UE issues a Mobile Originated Location Request (MO-LR) to the network, at which point the LMF obtains or determines the location of the anchor UE and stores the updated location information in its respective storage.

[0193] To locate the target UE 10 using ranging / sidelink positioning, the target UE issues an MO-LR to the network (1005) (e.g., via a Uu connection if the target UE is in coverage, or indirectly (e.g., via a ProSe UE-to-network relay or gateway function provided by the anchor UE), or by the anchor UE itself reporting an MO-LR on behalf of the target UE (e.g., after PC5 discovery or PC5 connection setup)) or the GMLC 37 (or other LCS client) issues an MT-LR to the network (1006). These location requests are typically sent to the AMF 32, which selects the LMF 34 (or RMF 36 or other management entity) to process the request (1007). In one example, the AMF sends a message to the target UE to use a location service proxy, i.e. redirects the target UE to use a location service proxy instead of the LMF in the core network, based on a policy, instruction, or location request received, for example, from the LMF 34 or GMLC, depending on the coverage status of the target UE and / or anchor UE and / or the information provided in the location request (e.g., latency requirements), and / or based on the deployment (e.g., NPN deployment). Upon receiving such a message, the target UE starts to discover a location service proxy and / or starts a ranging / sidelink positioning session with the location service proxy. Additionally or alternatively, the target UE sends information about the discovered location service proxy, and the AMF uses this information to send a message to the target UE to use the discovered location service proxy. Upon receiving such a message, the target UE starts a ranging / sidelink positioning session with the respective location service proxy. In the case of ranging, it is important that the LMF selected to process the location request of the target UE is the same as the LMF selected to process the location request and / or location determination of the anchor UE (e.g., of the ranging constellation 50) with which the target UE is performing ranging.Otherwise, problems will arise in ranging and / or sidelink positioning procedures, since the ranging measurements / results will end up in different LMFs if the target UE and anchor UE are served by different LMFs. Also, the ranging configuration and resource allocation (e.g., timing of which ranging reference signal to transmit on which frequency) will not match. To enable this, since the target UE and anchor UE communicate over PC5 / sidelink and thus the anchor UE and target UE are likely to be in the same area served by the LMF, the AMF 32 selects an LMF that serves a particular area that overlaps / corresponds to area information related to the target UE, such as a tracking area identifier (TAI) or gNB / cell ID received (e.g., from the NG-RAN or the target UE itself, e.g., as part of a location request or registration request or in a separate message). The AMF obtains information about the areas served by the LMF (e.g., set of tracking areas, set of gNB / cell IDs, set of coordinates indicating the area covered by the LMF) from the LMF itself or from the GMLC 37, UDR 39, where this information is stored. Alternatively, to increase the likelihood that AMF32 selects the same LMF, AMF32 selects an LMF that serves a majority of other UEs in an area that overlaps / corresponds to area information related to the target UE, such as a Tracking Area Identifier (TAI) or gNB / cell ID received (e.g., from the NG-RAN or the target UE itself).The AMF may communicate with the target UE (e.g. based on discovery information from the target UE regarding anchor UEs that the target UE has discovered via PC5 / sidelink, which the target UE has provided to the AMF (e.g. as part of the MO-LR or in a separate message), e.g. by the anchor UE providing the AMF with discovery information or connection setup information related to the target UE, e.g. by the anchor UE having information regarding the ranging constellation 50, e.g. by receiving a location request including not only information about the target UE but also information, e.g. identification information, of one or more anchor UEs used for ranging / sidelink positioning of the target UE, or e.g. by (e.g. when the target UE is not covered by the coverage area) If the AMF 32 has information about both the NG-RAN, the target UE, or one or more anchor UEs involved in ranging / sidelink positioning with the target UE (by receiving information from the NG-RAN, the target UE, or the anchor UE that the anchor UE is used to relay messages from the target UE (by acting as a ProSe UE-to-network relay or gateway when the target UE is outside the NG-RAN's range), the AMF checks whether the AMF is already serving one or more of the anchor UEs, and if so, selects the same LMF for the target UE using information about the LMF serving one or more of the anchor UEs or selected for one or more of the anchor UEs. If the AMF is not currently serving one or more of these anchor UEs, the AMF requests the UDM (not shown) to provide information about which AMF is the serving AMF for the UEs not served by the current AMF. The current AMF 32 can ask the serving AMF 32 (2) of that UE which LMF it selected for that UE, and then select the same LMF. Alternatively, the GMLC or UDR stores information about the serving LMF for each UE.The AMF (or LMF) obtains this information from or requests GMLC or UDR to provide this information when the target UE or anchor UE registers and / or issues a location request, so that the AMF can select the same LMF (or the LMF provides or requests the serving LMF the UE context of one or more anchor UEs).

[0194] In the case where the AMF has selected a different LMF for one or more anchor UEs than the target UE, if the LMF finds (e.g. based on ranging constellation information) that it does not have UE context information for both the target UE and one or more anchor UEs it needs to be involved with, the LMF 34 requests (1008) the other LMF 34(2) whether it has UE context information for the UE or UEs for which the UE context information is "missing" (e.g. using the NL7 reference point (specified in TS 23.273 and which needs to be extended for this purpose)) and, if the other LMF 34(2) has that UE context information, requests the other LMF 34(2) to perform a UE context transfer of the "missing" UE context information to this LMF (or vice versa), e.g. using steps 5 to 10 of the LMF change procedure of clause 6.4 of TS 23.273. If none of the LMFs has UE context information available for the "missing" UE, the LMF issues a request to the AMF to assign the "missing" UE to the same LMF (1009). If the AMF is not already serving the "missing" UE, the AMF verifies (1010) whether another AMF is serving the UE (e.g., by requesting a UDM) and, if not, issues a network-triggered service request to the UE. Otherwise, the AMF selects the same LMF as the serving AMF for the "missing" UE. Additionally or alternatively, the different LMFs selected for two or more UEs involved in ranging coordinate with each other before or during the ranging procedure, e.g., by exchanging ranging configuration parameters, synchronizing their clocks, exchanging schedule / resource information, exchanging security credentials, etc. (1011). This is done by extending the NL7 reference point. The LMFs may even be located in different core networks, e.g. to enable Inter-PLMN ranging, whereby two or more UEs performing ranging are served by different core networks and therefore by different AMFs and LMFs.The AMF, LMF, or other core network function determines that such a situation has occurred based on the identity (e.g., SUCI, User Information ID, PRUK ID) of the anchor UE or target UE discovered via PC5 / sidelink, or the PLMN ID, NID, CAG, or NCGI information provided during discovery via PC5 / sidelink or during / after PC5 connection setup and provided by the target UE or anchor UE to its AMF, LMF, or other core network function. For this purpose, the LMF sets up a connection to an LMF in another core network, e.g., via a service-based interface if the two networks are closely aligned, or via a tunnel, relay, or proxy connection, e.g., via a GMLC that communicates with the GMLC of the other core network, or via a NEF of the other core network, setting up such a connection. In case of roaming of a target UE or anchor UE, the respective UE is usually served by the AMF and LMF of the serving (i.e., visited) network, and therefore the AMF can select the same LMF in the same manner as described above.

[0195] Once the same LMF is selected for the target UE and the involved anchor UEs or the LMF has adjusted their configurations, the LMF can configure the target UE and the anchor UE to be able to perform ranging between the target UE and one or more anchor UEs (and possibly between the anchor UEs themselves). The configuration information includes for example a session or ranging constellation identifier for initiating a joint ranging session or for reporting the respective ranging measurements or results to the LMF, although ranging can also be performed "session-less", in which case the timing of the measurement, the signal characteristics or the frequency used is sufficient information for the target UE or anchor UE to determine which ranging procedure or to which other UE the measurement applies. For this purpose, the configuration information provided to the respective target UE or anchor UE includes an identifier of the target UE or other anchor UE, or an identifier related to a ranging reference signal configuration or a configuration item therein (e.g. a specific resource schedule), as described in other embodiments.

[0196] If a ranging constellation is associated with a set of group / domain credentials or authorization tokens, the target UE and / or anchor UE of the ranging constellation must provide proof of possession of the group / domain credentials or authorization tokens (e.g. by sending a correct response to an authentication / authorization request or sending a correctly signed token / message) when registering the target UE and / or anchor UE with the core network (usually with the AMF), preferably before the AMF selects an LMF, e.g. as part of a primary authentication procedure or as a separate procedure with the AMF and / or AUSF / UDM. If the AMF does not have this information, it requests the LMF, GMLC, UDR or UDM that stores this information as part of the ranging constellation information to provide it, or alternatively the LMF performs such a request or asks the AMF or AUSF / UDM to perform such a check. Similarly, if the ranging constellation information includes information on a closed access group identifier indicating a closed access group or closed network identifier or (private) network slice identifier (e.g. operated by a closed network) that the anchor UE or target UE needs to join or access in order to (temporarily) participate in the ranging constellation (e.g. to participate in ranging of the target UE), the AMF needs to check that the target UE or anchor UE can access that closed access group, NPN, or network slice, preferably before selecting an LMF (e.g. at the time the target UE or anchor UE registers with that AMF). Also, similarly, if the AMF does not have this information, it requests the LMF, GMLC, UDR, or UDM that stores this information as part of the ranging constellation information to provide this information, or alternatively, the LMF performs such a request or asks the AMF or AUSF / UDM to perform such a check.Alternatively or additionally, the AMF provides the LMF with necessary information (e.g., CAG ID, NPN ID, network slice ID of each UE) so that the LMF can perform this check. Similarly, when the ranging constellation information includes information about a set of target UEs that are served by a ranging constellation and thus e.g. (temporarily) participate in the ranging constellation, and the ranging constellation is indicated, e.g. by a target UE identity set and / or by a set of network identities (e.g., PLMN IDs) indicating which home network the target UE needs to subscribe / belong to in order to be served by that ranging constellation (i.e. whether ranging using an anchor UE of the ranging constellation can be performed for a visiting / roaming target UE that is subscribed / belongs to a PLMN different from the serving network of one or more anchor UEs of the ranging constellation), the AMF needs to check (e.g., at the time the target UE registers with that AMF), preferably before selecting an LMF for the UE, that the identity of the target UE is indeed in the list of target UE identities and / or that the identity of the network to which the target UE is attached / subscribed (e.g., HPLMN ID) is in the list of indicated network identities. If the AMF does not have this information, it requests the LMF, GMLC, UDR or UDM, which stores this information on the set of target UE identities and / or the set of network identities as part of the ranging constellation information, to provide this information, or alternatively, the LMF performs such a request or asks the AMF or AUSF / UDM to perform such a check. Alternatively or additionally, the AMF provides the LMF with the necessary information (e.g., the identity of the respective UE, e.g., SUPI and / or the home network identity (e.g., HPLMN ID)) so that the LMF can perform this check.Similarly, if the ranging constellation information includes a set of network identities (e.g., PLMN IDs) indicating which home network the anchor UE needs to subscribe / belong to in order to operate in a ranging constellation in a visited network (i.e., when the anchor UE is roaming / visiting a network different from its home network), the AMF should check that the identity of the network to which the anchor UE belongs / subscribes (e.g., HPLMN ID) is in the list of indicated network identities before selecting an LMF for the UE (e.g., at the time the anchor UE registers with the AMF). If the AMF does not have this information, it requests the LMF, GMLC, UDR, or UDM, which stores this information on the set of network identities as part of the ranging constellation information, to provide this information, or alternatively, the LMF performs such a request or asks the AMF or AUSF / UDM to perform such a check. Alternatively or additionally, the AMF provides the LMF with necessary information (e.g., the identity of each UE, e.g., SUPI and / or home network identity (e.g., HPLMN ID)) so that the LMF can perform this check.

[0197] Detailed architecture and procedures for distributed localization 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, with the assistance of a ranging service (RS), obtains location coordinates obtained from a location service (LS).

[0198] In an embodiment related to distributed localization based on ranging measurements by the anchor UE 14, one of the anchor UEs 14 receives a request for location (e.g., geographic) coordinates from the device UE 10, either directly or via another device UE close to the ranging constellation 50, and acknowledges the request. The ranging measurements corresponding to the device UE 10 and the ranging constellation 50, i.e., performed on ranging reference signals between the device UE 10 and one or more anchor UEs of the ranging constellation, are used by the anchor UE 14 to locally calculate location coordinates of the device UE 10 (using any of the concepts described in this disclosure) based on the ranging measurements by the device UE 10 and its own location information obtained from a location service or an additional location module provided to the anchor UE 14.

[0199] It should be noted that the anchor UE 14 also informs the device UE 10 of the local coordinate system used by the ranging constellation 50 and the expected accuracy level 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 informs the device UE 10 of the different types of coordinate systems supported by the ranging constellation 50. The device UE 10 selects one of the supported coordinate systems or lets the anchor UE 14 decide on a default coordinate system for the given device UE 10 depending on its device characteristics. It should be noted that the local coordinates using such coordinate systems can be converted to geographic coordinates by the anchor UE 14 or other devices UE 10 that can act as a proxy for location services, or by the location services 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 by the device UE 10. For this purpose, the ranging capable UE sends a message over a secure interface to an LMF 34, RMF 36, or other location service and / or ranging service in the core network or provided by the access device, or a proxy of an LMF 34, RMF 36, or other location service and / or ranging service provided by another ranging capable UE (e.g., anchor UE 14), the message including distance and / or angle measurements (e.g., based on ranging reference signals) and optionally including ID and / or timing information, or distance and / or angle calculations (e.g., based on ranging measurements), as well as other information such as the location coordinate system to be used, and optionally including altitude and / or speed / accelerometer information, so that, upon receipt of the message by the LMF 34, RMF 36, other location / ranging service, or location / ranging service proxy, a response message is returned including the resulting location coordinates calculated using the specified optional location coordinate system or a default (e.g., geographic) coordinate system.

[0200] In order to enable the LMF 34, RMF 36 or other location services and / or ranging services, or proxies thereof to calculate the position or distance / angle, the device UE 10 grants authorization to the LMF 34, RMF 36 or other location services and / or ranging services, or proxies thereof, by providing them as part of the same or a subsequent message with authorization credentials that can be used to authenticate / verify that the authority is genuine (i.e. granted by the device UE 10), e.g. by performing a respective authentication procedure with the device UE 10, or by verifying whether the credentials match or can be securely correlated with credentials of the device UE 10 previously stored in the LMF 34, RMF 36 or other location services and / or ranging services, or proxies thereof, or core network functions (e.g. UDM / AUSF), and / or by granting authorization therefor by providing consent in a subscription (e.g. by UDM) or by providing consent through a Network Publication Function (NEF). The message sent by the device UE10 to grant consent for this contains several fields / payloads containing information about the consent given, e.g. validity period, the entity to which the consent has been given (e.g. a Location Service Proxy (provided by the particular UE whose identity is included)), credentials or tokens that need to be provided by the given entity before being allowed to participate in the calculation of the position or distance / angle of the device UE10.If a group / domain credential or authorization token, or a closed access group, NPN, or (private) network slice is associated with a ranging constellation that is used to secure communication between UEs of the ranging constellation and / or to restrict communication only between UEs that belong to that group / domain / closed access group / NPN / slice, the device UE 10 only needs to provide consent once (e.g., by including the ranging constellation ID, group / domain credential, and / or closed access group, NPN, or (private) network slice information with which the consent is associated in a message that the device UE 10 sends to the LMF 34, RMF 36, or other location and / or ranging service or their proxy, or other management entity) so that all UEs of the ranging constellation can participate in the calculation of the location or distance / angle of the device UE 10. For example, this is done during a message exchange when the target UE joins the ranging constellation (e.g., when issuing a request for ranging or location estimation to the LMF or its proxy). The consent is also stored in the UDM or GMLC (usually in the home network of the target UE) and verified, for example, by the AMF or other core network function. The consent is also provided by the application managing the ranging constellation and / or the involved UE (through the NEF), for example, by providing it implicitly or explicitly in the ranging constellation configuration information it sends to the LMF or other management entity.

[0201] Similarly, a ranging capable UE may use a similar message, also including location information or a device or reference point identifier, to request a location service and / or ranging service (or their proxy) to provide / calculate / return the distance and / or angle between the ranging capable UE and a specified device or reference point, and the LMF34, RMF36 or other location service and / or ranging service (or their proxy) then returns the resulting calculated distance and / or angle.

[0202] In another (alternative) embodiment related to distributed localization based on ranging measurements by anchor UE 14, the ranging constellation 50 is configured and deployed in an indoor environment or a known area of ​​interest so that it can have its own local coordinate system relative to a reference geographic coordinate system. A device UE 10 approaching the ranging constellation 50 and authorized to use the ranging constellation 50 requests location coordinates from the anchor UE 14 of the ranging constellation 50. Upon receiving the request, the anchor UE 14 itself or a head device of the ranging constellation 50 on behalf of the anchor UE 14 selects at least one (usually two or three) of the anchor UE 14 of the ranging constellation 50 to perform ranging measurements with the device UE 10, so that the selected device is within the requested ranging distance of 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 initiates ranging measurements with the device UE 10, for example in a synchronized or coordinated manner, to obtain ranging measurements. The ranging measurements are used to determine the location of the device UE 10 in the local coordinate system of the ranging constellation 50 by the head device of the ranging constellation 50 or by a combination of ranging and location services (or their proxies). A coordinated manner refers to performing ranging measurements ordered in time to avoid all measurements being started at the same time and causing mutual interference. It also means performing ranging measurements relatively close in time to obtain accurate results when the device UE 10 is moving.

[0203] It should be noted that in order 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 given moment), information embedded / added / multiplexed in the ranging reference signal (e.g., identifier), and / or ranging measurements / results are communicated to the second UE only if the second UE is authorized to use the ranging reference signal of the first UE. In order to prevent tracking of the UE based on the ranging reference signal and / or positioning message broadcasted by the UE, the identification information and / or resources (timing / frequency) of the ranging reference signal and / or positioning message are randomly allocated. For example, the signals / messages follow a random-looking pattern known only to authorized devices instead of following a well-known or deterministic pattern (e.g., a periodic pattern of signals / messages transmitted at a periodic / specific time / frequency). Additionally, after each ranging session, the UE needs or must request to receive a new / new authorization and / or obtain a new / new 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.

[0204] In one example, the device UE 10 approaches an area and, if ProSe-based ranging / localization services are authorized, is provided with ProSe discovery parameters (e.g., ProSe service / application identifier for ranging / localization services, or discovery key for discovering anchor UE and / or ranging / localization services). Based on these ProSe discovery parameters, the device UE 10 can discover other ranging-capable UEs (e.g., anchor UE 14) that are in the area, and these UEs use one of the ProSe discovery procedures. Once discovery is performed, the anchor UE 14 provides the ranging / localization service requested by the device UE 10 with certain 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 discovery 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 is equipped with beamforming capabilities so that ranging measurements can be targeted to a particular anchor UE 14, and this "angle" information is used to determine the location of the device UE 10.

[0205] In a further (alternative) embodiment related to distributed localization based on ranging measurements by anchor UEs 14, the device UE 10 receives an updated list of anchor UEs 14 located in its vicinity, for example from the LMF 34 or RMF 36 or other management entity. It should be noted that the LMF 34 and / or RMF 36 or other management entity keeps creating and updating this list of anchor UEs 14, resulting in a constantly updated constellation of rangeable UEs whose positions are known a priori to the LMF 34 and / or RMF 36 or other management entity. Optionally, to provide control to the network operator, the device UE 10 is requested to report to the LMF 34 and / or LMF 36 or other management entity on measurements (e.g. performed on ranging reference signals received from one or more anchor UEs) together with an indication of the position of the device UE 10.

[0206] 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 needs 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 authorize the device UE 10 to discover the anchor UE 14 by a (PC5) discovery message.

[0207] When device UE 10 approaches and comes within ranging distance of one of the anchor UEs 14 of the ranging constellation 50, it is assisted in obtaining its location coordinates through ranging measurements without actually being located by the network access device 20 and / or LMF 34.

[0208] In a further embodiment related to distributed localization based on ranging measurements by an anchor UE 14, which may be used as an alternative or in combination with the corresponding embodiment above, an out-of-coverage device UE 10 requests its current location information calibrated for ranging measurements with the device UE 10 from a communicatively coupled anchor UE 14, for example by sending a message with measurement results related to a ranging reference signal (such measurement results including, for example, an ID of the device or an ID of the ranging reference signal and / or timing information) and / or estimated range / angle to the anchor UE 14, and optionally including information on the coordinate system used, and optionally including altitude and / or speed / accelerometer information. The type of message (e.g. PC5_Location_Request or RRCLocationRequest) indicates to the anchor UE 14 that the device UE 10 is requesting location information based on the provided information, and the anchor UE 14 returns this information (after calculation) to the device UE 10 in a response message.

[0209] Similarly, the device UE 10 uses a similar message that also includes location information or device or reference point identifiers to 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, and the anchor UE 14 then returns the resulting calculated distance and / or angle. The anchor UE 14 may know its own location or may request its own location coordinates from the LMF 34 or RMF 36 or other location service of the core network 30 (e.g., a network controller device) based on positioning measurements by the network access device 20 (e.g., a gNB) and convert the ranging measurements of the device UE 10 into local location coordinates of the device UE 10.

[0210] Alternatively, the anchor UE 14 reports the ranging measurements of the device UE 10 together with its device ID to the LMF 34 or RMF 36 to obtain the location coordinates of the device UE 10, which are then calculated by the LMF or RMF.

[0211] Alternatively, the location coordinates of the anchor UE 14 may be shared with the device UE 10 and the device UE 10 may use its own ranging measurements and the location coordinates of the anchor UE 14 to calculate its own location coordinates.

[0212] In a further (alternative) embodiment related to distributed localization based on ranging measurements by anchor UEs 14, anchor UEs present in the ranging constellation 50 are configured to advertise (ranging-based) positioning services (or proxies thereof) as proximity services. It should be noted that in this case some of the anchor UEs 14 need to be assigned to the ranging proximity service. In this case, the LMF 34 or RMF 36 or other management entity needs to interact with a Direct Discovery Name Management Function (DDNMF) or Policy Control Function (PCF) that is responsible for the assignment of discovery parameters to UEs. Upon connection, subscription and / or authorization to a proximity service for ranging-based positioning, the device UE 10 receives (e.g., via a PC5 sidelink channel) discovery keys / parameters to access the ranging / positioning service (or its proxy). The device UE 10 then securely transmits (or receives) discovery messages for the ranging-based positioning services (or its proxies) of anchor UEs 14 of the ranging constellation 50 (e.g., via a PC5 sidelink discovery message).

[0213] The management entity, PCF, AUSF, LMF 34, or RMF 36 should provide credentials to the device UE 10 (e.g., during initial provisioning of the ranging / location service on the device UE 10 or during an authentication / connection setup procedure between the device UE 10 and the anchor UE 14, including message exchanges between the anchor UE 14 and the respective network function before the anchor UE 14 forwards data to the device UE 10 and / or message exchanges between the device UE 10 and the respective network function via a relay connection via the anchor UE 14), and the device UE 10 should use these credentials to securely connect to the ranging / location service (or its proxy) and / or use these credentials to protect data that the device UE 10 sends to or receives from the ranging / location service (or its proxy). Alternatively, the device UE 10, together with a management entity, PCF, AUSF, LMF 34, or RMF 36, derives credentials (e.g., keys) that it uses to securely connect to the ranging / location service (or its proxy) and / or to protect data that it sends to or receives from the ranging / location service (or its proxy) based on a pre-configured set of credentials (e.g., root credentials in the SIM, or a session key, e.g., Kamf or Kausf, or an application key).

[0214] Upon receiving (or transmitting) the discovery message, the anchor UE 14 of the ranging constellation 50 replies (or includes) location and / or ranging measurements or calculated ranging results, depending on its device capabilities. This can be accomplished by the discovery message or by configuring lower protocol layers (e.g., the physical (PHY) layer) to initiate transmission of positioning signals, communicating timing, frequency, and / or identification information of the positioning signals to the device UE 10 (e.g., over a PC5 interface), and collecting UE measurements of the received positioning signals or ranging results calculated based on the measurements over the PC5 interface.

[0215] The anchor UE 14 provides 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 or desired ranging parameters) via direct device-to-device communication (e.g., using sidelink / PC5) or discovery upon successful discovery, e.g., as described in the above embodiments. This approach is useful for out-of-coverage device UE 10, since the device UE 10 can subsequently only receive these parameters from other ranging capable UEs via direct device-to-device communication (e.g., using sidelink / PC5) or discovery. Alternatively, the device UE 10 receives the ranging parameters of the anchor UE 14 when it joins ranging services, location services, and / or ranging-based positioning services, e.g., after authentication and authorization.

[0216] In one embodiment, if there are several ranging capable UEs, e.g., anchor UEs 14 that have responded with ranging reference signals (e.g., discovery messages) to the device UE 10 or have spontaneously transmitted ranging reference signals (e.g., discovery messages), the device UE 10 estimates the distance and / or angle based on timing measurements for each ranging reference signal (e.g., discovery message) and uses the estimated distance and / or angle to estimate its location, e.g., by triangulation / trilateration. For this purpose, the UE (e.g., anchor UE 14) transmitting the ranging reference signal (e.g., discovery message) transmits a synchronization signal and / or timing information to the receiving device (e.g., device UE 10). Alternatively or additionally, the timing of the resource scheduled for discovery (e.g., sidelink discovery pool) or the ranging / ranging reference signal pool can be used to determine the transmission start time of the ranging reference signal (e.g., discovery message). The ranging reference signal (e.g., discovery message) includes time stamp information regarding the time when the ranging reference signal was transmitted, or time difference information (e.g., t4-t1 and / or t3-t2 in case of FTM-based technique). The ranging reference signal (e.g., discovery message) includes radiation angle information. The device UE 10 does the same with the ranging reference signal (e.g., discovery message) to another ranging capable UE (e.g., anchor UE 14). Alternatively, when only a few, e.g., one UE 14, respond to the device UE 10 while the clocks of the device UE 10 and anchor UE 14 are synchronized, and / or the ranging reference signal (e.g., discovery message) includes location and time of launch (TOD) information, the device UE 10 calculates the distance based only on the ranging reference signal (e.g., discovery message) and can estimate its position if sufficient information is available (e.g., if the device UE 10 can also measure the angle and / or if information regarding altitude is provided to / by other UEs). This alleviates the need for the device UE 10 to send other messages (such as specific ranging / position / sounding reference signals) to the anchor UE 14 for positioning information.

[0217] In one embodiment, to improve accuracy, the ranging reference signal (e.g., discovery message) is transmitted in multiple bands / frequencies, uses a wider bandwidth, or is co-located / pre-post-located with the ranging reference signal. Some or all of the content of the discovery message (e.g., IDs of other ranging devices) or a copy thereof is transmitted as the payload / encoded data of the ranging reference signal. Similarly, some or all of the content of the ranging reference signal and / or ID, type, or device identification information, e.g., related to the location / sounding signal, is transmitted as the payload / encoded data of the discovery message.

[0218] More details on using ProSe discovery messages for ranging In the following embodiments, some concepts of ranging-based positioning based on discovery messages are described, which can be adapted to use positioning signals transmitted at the PHY layer, e.g., as in existing positioning techniques or as described in the above embodiments.

[0219] In an embodiment related to ProSe Open Discovery with ToF measurements or carrier phase based ranging, which may be combined with any other embodiment or implemented independently, the discovery message in ProSe Open Discovery may be enhanced to include ranging capability. This may be achieved by configuring the anchor UE 14 to transmit discovery messages according to a given timing schedule known to the device UE 10 so that the devices may be synchronized. The discovery message includes an identifier indicating a ranging service, a location service, or a ranging-based positioning service (or a proxy thereof), such as a relay service code (RSC), a service identifier, or an application code. Furthermore, the discovery messages are enhanced to include the (fixed) identity (e.g., L2 identity) of the anchor UE 14 (to allow the device UE 10 to identify the anchor UE 14), the location and / or positioning information of the anchor UE 14 (e.g., the location of the anchor UE, or the carrier-phase-based positioning signal used to transfer the discovery message itself), and / or timing information (e.g., the time the message was sent, or the time the Model B discovery request message was received if the discovery message is a Model B discovery response message). These discovery messages are integrity protected using a discovery user integrity key (DUIK). Based on this, the device UE 10 can check the integrity of the received discovery messages, identify the anchor UE 14 delivering the discovery message, identify the ranging service, location service, or ranging-based positioning service (or a proxy thereof) based on the identifier, and extract the distance information and the timing when the discovery message was received from the positioning information.

[0220] In an embodiment related to restricted discovery by round trip time (RTT) measurement, which may be combined with any other embodiment or implemented independently, a discovery message in ProSe restricted discovery may be enhanced to include ranging capability. This may be achieved by enhancing the first message (i.e., discovery message) transmitted by the device UE 10 to include an identifier (e.g., RSC) indicating ranging service, location service, ranging-based positioning service, and / or ranging / location request. The device UE 10 is configured to start a timer when the discovery message is transmitted for the first time. The device UE 10 then receives a response from the anchor UE 14 including the position Pa of the anchor UE 14, which may be verified and decrypted using a discovery key received by the device UE 10 after registering or subscribing to 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 may then be calculated as RTT*c / 2. Because the device UE 10 also receives the position of the anchor UE 14, the device UE 10 knows that its position is on the circumference of a circle with a radius of RTT*c / 2, the centre of which is the position Pa of the anchor UE 14.

[0221] It should be noted that the anchor UE 14 requires significant time to process the message, i.e. to decode and verify the initial discovery message sent from the device UE 10. Therefore, the RTT calculation should not include the processing time of the anchor UE 14 and / or the time that the anchor UE 14 waits (e.g., according to scheduled resources) until it sends a response to the initial discovery message, i.e., the time when the packet is not in the air. In order to exclude this processing time and / or waiting time from the measured RTT, the reply from the anchor UE 14 also includes information of the processing time and / or waiting time at the anchor UE to process the received discovery message and send a reply (e.g., time t3-t2 for FTM, UERX-TX for LTE / NR-based RTT measurement), and the device UE 10 can correct the RTT estimation accordingly. Alternatively, the device UE 10 utilizes the timestamp values ​​of the exchanged messages and / or the timestamps sent separately by the anchor UE 14 in addition to the discovery message using normal messages when the time is measured using a ranging reference signal, e.g., PRS. The device UE 10 then uses the timer and timestamp values ​​to subtract the processing time of the anchor UE 14. The device UE 10 can then use two or more of such measurements to estimate its own location. By including the timing information as part of the discovery message, the device UE 10 and anchor UE 14 do not need to exchange additional measurement reports, nor do they need to send separate PRS / SRS signals in the case of ProSe / ranging based sidelink devices, since the discovery message is sent anyway.

[0222] Combination with non-3GPP positioning In a further embodiment related to distributed localization based on ranging measurements by the anchor UE 14, which may be used as an alternative or in combination with the corresponding embodiment above, the anchor UE 14 uses a non-3GPP® communication channel (e.g., Wi-Fi®, Bluetooth®) 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., Wi-Fi® access points or Bluetooth® beacons) in the area, thereby assisting and / or improving positioning accuracy and location acquisition time across the ranging constellation. It should be noted that depending on the device capabilities, non-3GPP® information is also broadcast by the device UE 10 and / or anchor UE 14. This beacon information is transmitted to the LMF 34 and / or RMF 36 when the anchor UE 14 observes the beacon information or when requested by the LMF 34 and / or RMF 36.

[0223] The LMF 34 and / or the RMF 36 are communicatively coupled to a non-3GPP® positioning system (e.g., a Wi-Fi® positioning system or a Bluetooth® positioning system) to obtain (geographical) location coordinates based on the beacon information. It should be noted that the non-3GPP® positioning system (e.g., a Wi-Fi® positioning system) can be used when there is a discontinuity in the positioning information system due to non-coverage, or can be used at all times in addition to the conventional 3GPP® positioning service. The device UE 10 uses the prior knowledge of the beacon information obtained from the broadcast messages (if available) of the non-3GPP® technology (e.g., Wi-Fi® or Bluetooth®) to assist the ranging service in determining and tracking the orbit information, as described in one of the above embodiments. Furthermore, the beacon information observed by the device UE 10 is 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 the anchor UE 14 are time synchronized, the timing information of the 3GPP® RAT can be combined with the beacon information obtained from the non-3GPP® RAT to estimate the location of the device UE 10 at a particular time and to assist in tracking the trajectory. Alternatively, even if the device UE 10 is not time synchronized with any anchor UE, the non-3GPP® beacon information can be linked to the timing of the entire ranging constellation 50 or a particular anchor UE 14. After the device UE 10 is time synchronized with the anchor UE 14 and / or the ranging constellation 50, depending on the application, either the device UE 10 or the anchor UE 14 calculates the clock time offset.

[0224] Alternatively, two ranging capable devices may support 3GPP-based and non-3GPP-based ranging methods and / or use licensed and unlicensed bands to perform ranging measurements. For example, the devices support Time Difference of Arrival over PC5 / sidelink as 3GPP-supported methods, and Wi-Fi fine timing measurements or Bluetooth beacons, RTT, carrier phase ranging measurements, or AoA / AoD measurements. The ranging capable devices express support for these non-3GPP ranging methods in discovery messages (e.g., PC5 ProSe discovery messages) and / or by sending messages to the other ranging device upon establishing a connection between the two ranging capable devices. The ranging capable devices indicate a preference among all supported 3GPP and non-3GPP ranging methods and / or the devices select a preferred set of ranging methods based on configured policies or environmental / context information, application requirements, and / or accuracy requirements. A ranging capable device may use multiple ranging methods simultaneously and / or sequentially.

[0225] In another embodiment, the device UE 10 requires positioning services from a positioning constellation and an anchor UE 14 is present around it. The device UE 10 is a smart watch and the anchor UE 14 is a smartphone. The exact location of the anchor UE 14 is known to the management entity by standard positioning signals transmitted by an access device, e.g., a gNB. In this case, the management entity determines the approximate location of the device UE 10 taking into account that the device UE 10 is in range of the anchor UE 14 and the known location of the anchor UE 14.

[0226] Randomized Ranging Reference Signal In an embodiment related to positioning signals from the anchor UE 14 or target UE 10, which may be combined with any other embodiment or implemented independently, a configuration entity (e.g., a management entity) assigns the anchor UE 14 or target UE 10 an allocation of positioning signals that appears random, e.g., non-regular transmission times / schedules, positioning signal IDs, and / or timing / frequency patterns. 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 are randomly or seemingly randomly selected from a set of available positioning signals, which are identified by positioning signal IDs and whose characteristics are pre-configured by the configuration entity. Also, the resources used to transmit the positioning signals are 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 is not a fixed value. Therefore, it is difficult to track UEs transmitting positioning signals over sidelink channels, and UEs can only use those positioning signals if they are informed of their timing and identity over time. The identity of the positioning signal has a one-to-one or many-to-one relationship with the anchor UE identity or target UE identity at a given time, or a many-to-many relationship with a set of anchor UE or target UE identities at a given 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 and identity and / or UE identity of the positioning signal over time. The positioning signals p1, p2, ..., pi above may be standard signals (e.g., as defined in TS36.211) or may differ, e.g., in waveform, bandwidth, preamble, carrier, guard band, and / or include patterns indicative of the positioning signal ID, anchor UE identity, or target UE identity, and correspond to different positioning signal IDs, anchor UE identities, or target UE identities at times t1, t2, ..., ti.This positioning signal ID, anchor UE identity, or target UE identity determines, for example, a pseudo-random sequence (e.g. associated with the positioning signal ID, anchor UE identity, or target UE identity at a given moment), or an encrypted / scrambled positioning signal ID, anchor UE identity, or target UE identity transmitted as part of, encapsulated by, or via the positioning signal, or determines the frequency shift of the positioning signal. The anchor UE identity, target UE identity, and / or positioning signal ID are also used to determine / select the radio resources to be used for transmitting / receiving the positioning signal. For this purpose, the access device or the management entity defines resources per location signal ID, anchor UE identity, or target UE identity and provides resource allocation information to the involved UEs (e.g. all UEs that are part of the constellation). The management entity needs to ensure that multiple anchor UEs and / or target UEs in the vicinity do not interfere with each other. Thus, the management entity needs to assign anchor UE identities, target UE identities, and / or positioning signal IDs at times t1, t2, ..., ti to each anchor or target UE in the area such that they do not collide (e.g., they do not use the same radio resource elements at the same time) and inform the involved UEs (e.g., all UEs in the ranging constellation) of their respective identities using a secure connection or (encrypted messages that only the intended recipient can decrypt). Alternatively, the positioning signal ID, anchor UE identity, or target UE identity may be self-selected by each anchor UE 14 or target UE 10 according to, for example, a pre-configured randomization function (e.g., based on UTC time / System Frame Number (SFN)), which is securely shared with the UEs of the constellation and inform the involved UEs (e.g., all UEs in the ranging constellation) of their respective identities using a secure connection or (encrypted messages that only the intended recipient can decrypt).Alternatively, the positioning signal ID, anchor UE identity, or target UE identity is self-selected by the respective anchor UE 14 or target UE 10 according to a pre-configured pseudo-randomization function (e.g., based on UTC time / system frame number (SFN)), whereby the configuration of the pseudo-randomization function is securely shared with UEs in the ranging constellation, and each UE uses this configuration to derive the same identity.

[0227] In a further embodiment related to the previous one, the management entity utilizes a random-looking allocation of positioning signals for the admission and revocation of the service. The management entity distributes, i.e. discloses, the random-looking allocation of positioning signals assigned to the anchor UE 14 or target UE 10 only to the devices UE 10 or anchor UE 14 that are approved to use the service, e.g. approved during the initial configuration phase. A given positioning signal pi of the random-looking positioning signals p1, p2, ...pi, ...pj has a limited validity period, e.g. a few seconds, minutes, etc. In this case, if the UE 10 is already configured with positioning signals pi+1, pi+2, ..., the UE 10 is prevented (revoked) from using the ranging service 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 relies. Alternatively, the management entity discloses to the UE 10 only those positioning signals assigned to the anchor UE that are valid for a very limited time, so that the UE 10 automatically loses access to the service as soon as the limited time has elapsed. The two alternatives described above provide a practical scheme for revoking the use of ranging / location services without having to update the credentials of all associated devices to reflect the revoked authorization.

[0228] Carrier Phase Based Ranging In one embodiment related to carrier-phase based ranging in the sidelink direction, which may be combined with any other embodiment or implemented independently, two or more anchor UEs 14 transmit positioning signals over the sidelink characterized by very specific carrier signatures. The device UE 10 is strictly time-synchronized with the two or more anchor UEs 14, receives positioning signals from the two or more anchor UEs, measures the number of carrier cycles CCi of each anchor UE positioning signal since transmission, derives the distance Di to each anchor UE 14 as Di=CCi*λ, where λ denotes the wavelength of the positioning signal, and the device UE 10 estimates its position P based on the measured Di and knowledge of the positions of the anchor UEs 14.

[0229] Measuring the number of carrier cycles is achieved by decoding, calculating and using phase measurements of the code in the signal. The calculation of the number of cycles is based on decoding a known pseudorandom code (PRC) in the signal, and for each signal it is found at what "point" the PRC is at compared to an internal clock reference, from which a rough value for the number of cycles CC can be calculated. The finer part of CC (a fraction of a carrier cycle) can be obtained from the carrier signal phase measurement.

[0230] In one embodiment related to differential carrier phase based ranging, which may be combined with any other embodiment 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 located at a well-known location (e.g., (x,y,z) coordinates) within the ranging constellation 50 and measures the positioning signals from the other two or more anchor UEs 14 or wireless access devices 20.

[0231] The device UE 10 is strictly time-synchronized with the head anchor UE and anchor UE 14, receives positioning signals from two or more anchor UEs 14, measures the carriers of the positioning signals and estimates its position P at time t based thereon, receives from the lead anchor UE a current positioning signal error E_Lead (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 actual position of the lead anchor UE (e.g. pre-configured)) measured by the lead anchor UE itself at time t, and obtains an enhanced differential positioning estimate by combining P and E_Lead since E_Lead is correlated with the error experienced by the device UE 10. For example, at time t, P_Corrected=P-E_Lead It is.

[0232] In the above description, all communication links are based on PC5 communication interfaces between two or more UEs.

[0233] In one embodiment related to RTT carrier phase based ranging between device UE 10 and anchor UE 14 (or wireless access device 20), which may be combined with any other embodiment or implemented independently, anchor UE 14 (e.g., head anchor UE) (or wireless access device 20) transmits a positioning signal using a well-defined carrier signal. The anchor UE 14 (or wireless access device 20) starts counting the number of carrier cycles CC.

[0234] As soon as the positioning signal is received, the device UE starts retransmitting (a copy of) the received positioning signal or generates a (well-defined) carrier signal itself and transmits it towards the anchor UE 14 (or wireless access device 20). The device UE 10 counts and transmits CC_delay, the number of carrier cycles it took from when the signal was first received until it started retransmitting the signal or started transmitting a carrier signal generated by the device UE 10 itself. As soon as the anchor UE 14 (or wireless access device 20) receives a signal from the device UE 10, it stops its counter and reads the value of CC. Then, the distance D between the device UE 10 and the anchor UE 14 itself is calculated as D=0.5*(CC-CC_delay)*λ where λ refers to the wavelength of the carrier signal.

[0235] This embodiment may be enhanced 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.

[0236] Furthermore, the anchor UE 14 (or wireless access device 20) needs to wait one carrier cycle length to be able to correctly determine the signal returned from the device UE 10. Therefore, unless it can recognize the signal using a specific preamble, the CC measurement may be one carrier cycle high at the point where the timer can be stopped. Therefore, a preamble is used to recognize the signal from the device UE 10. Also, a preamble is added so that the device UE 10 can recognize the positioning signal for carrier-based ranging from the anchor UE 14 (or wireless access device 20).

[0237] In one embodiment, which may be combined with any other embodiment or implemented independently, the device UE 10 and / or anchor UE 14 (or access device 20) need to correct the length, placement, and orientation of the antenna used to perform the ranging measurement, especially the carrier phase based ranging. For example, in a car, the antenna is very long and / or located very far 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 each antenna needs to be added to the distance D according to the above formula or otherwise corrected. Similarly, the distance between the transmitter 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 needs to be added or otherwise corrected. For this purpose, device UE1 and anchor UE14 (or access device 20) exchange information about antenna configuration, antenna ports (possibly with information about signals transmitted through those ports), antenna length, antenna placement / location with respect to a reference coordinate, and / or azimuth / angle / direction with respect to a reference direction or magnetic north (e.g., represented by a vector in a coordinate system) through discovery messages, connection setup messages, ranging session start messages, and / or configuration messages. Information about antenna ports used to transmit signals is encoded as part of the ranging reference signal.

[0238] In one embodiment, which may also be combined with any other embodiment or implemented independently, the device UE 10 and / or anchor UE 14 (or access device 20) exchange information through discovery messages, connection setup messages, ranging session initiation messages, and / or configuration messages regarding the dimensions of the object (e.g., vehicle) carrying or surrounding the device UE 10 or anchor UE 14 (or access device 20), the relative position (e.g., distance, angle, and / or use of a relative coordinate system) of the device UE 10 or anchor UE 14 (or access device 20), and / or one or more antennas related to the surface, center of gravity, or other (pre-configured or determined) reference point of the object carrying or surrounding the device UE 10 or anchor UE 14 (or access device 20). This information is used to adjust the calculated distance and / or angle between the devices (e.g., between the device UE 10 and anchor UE 14) taking into account the distance to the object's surface, e.g., to prevent collisions, or to adjust the calculated location of the device. Alternatively or additionally, the LMF or device involved in ranging or sidelink positioning of device UE 10 and / or anchor UE 14 obtains information regarding the relative position of the device or antenna with respect to the object's dimensions, surface, center of gravity, or reference points, and / or detailed antenna information (e.g., antenna length, ports) based on the identification information of device UE 10 or anchor UE 14 (or access device 20) from a database storing this information regarding device UE 10 and / or anchor UE 14 (and / or access device 20).

[0239] In an embodiment related to carrier sensing using multiple carriers, which may be combined with any other embodiment or implemented independently, LTE vehicle-to-all (V2X) communication may be used, supporting single-carrier frequency division multiple access (FDMA) and 10 MHz and 20 MHz channels. The channel is divided into 180 kHz resource blocks containing 12 subcarriers of 15 kHz each. In 5G R16 V2X, the sidelink may operate in frequency range 1 (i.e., FR1, between 410 MHz and 7.125 GHz) and frequency range 2 (i.e., FR2, between 24.25 and 52.6 GHz). Transmission may be performed using orthogonal frequency division multiplexing (OFDM). The number of slots per subframe and the subcarriers of the OFDM waveform may be varied.

[0240] When considering carrier phase based sensing, it may be advantageous to use higher frequencies since shorter wavelengths result in lower error in distance measurements. Additionally, 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. The receiver may convert the N phase measurements at the N frequencies into bias range measurements based on the N phase measurements.

[0241] For example, consider a typical positioning reference signal (PRS), where the PRS sequence r l,nsIt is observed that (m) involves transmission on a specific subcarrier / symbol defined in 3GPP TTS36.211, where ns is the slot number and 1 is the OFDM symbol. At the beginning of each OFDM symbol, a pseudo-random sequence is transmitted 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, 1) and the physical cell identity. Note that the cell specific frequency shift is given by NCell-ID mod6. The effective reuse factor of the existing PRS sequence is 6. When a UE configures 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 an identifier or be assigned / configured with an identifier so as not to collide with other nearby anchor UEs.

[0242] Furthermore, the PRS sequence is transmitted in predefined positioning subframes grouped by a number of consecutive subframes called positioning occasions that occur periodically (e.g., every 160, 320, 640, or 1280 subframes (or milliseconds)), where the number of consecutive frames is 1, 2, 4, or 6 (TS 36.211). 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.

[0243] In the following embodiment of carrier phase based ranging, the receiver first identifies the PRS itself. This is based on the timing (in which frame and slot), frequency (in which carrier), identity (which identity is used to generate the pseudo-random sequence), duration (how many frames are used to transmit the PRS), and periodicity (in every how many frames the PRS is transmitted). Since the anchor UE does not have a cell identity like the base station, the UE uses an identity, e.g., randomly selected, to generate the pseudo-random sequence. The PRS used by the anchor UE is also determined by a management entity. The management entity also configures the anchor UE with a policy that determines the preferred PRS parameters or PRS signal, which includes an alternative PRS signal, e.g., in case the preferred PRS signal is used by a different anchor UE nearby. Furthermore, for carrier phase based ranging, the receiver detects the received phase of each carrier at each symbol / resource element used by the PRS signal, e.g., at the beginning of the symbol used. Because not all subcarriers are received simultaneously due to the manner in which the PRS is defined, the receiver can measure the phase of different carriers at different times and (due to the periodicity of the subcarriers) derive the received phase of all carriers as if they were all received simultaneously. The receiver can map the measured phases of the different subcarriers to a range measurement.

[0244] It is worth noting that since multiple carriers are used, the UE does not need to monitor all of them. For example, to achieve a suitable accuracy, it is sufficient for the UE to monitor only N' subcarriers, e.g. the first N' subcarriers of the PRS signal. The value N' is configured by the management entity. Furthermore, reducing the number of subcarriers that need to be tracked helps to reduce the delay and energy consumption for obtaining ranging measurements and transmitting possible ranging-related measurements.

[0245] Furthermore, if N' subcarriers are sufficient, a possible approach is to perform a measurement every N'*symbol_time seconds to obtain a measurement if the carriers used for carrier-phase based ranging / positioning are selected to be adjacent to each other. For example, if N'=6, it is possible to perform a measurement on the first 6 subcarriers and a second measurement on the next 6 subcarriers.

[0246] An alternative is, for example, to alternate the allocation, for example using subcarrier i=2n (n=1,...,N') for a measurement and subcarrier i=2n+1 (n=1,...,N') for a second measurement. This spacing has the advantage of allocating carriers more evenly. On the other hand, if the PRS is transmitted continuously, the ranging estimate is also updated every time a new symbol using a new preferred carrier is received, by using a windowing technique that keeps track of the last N' preferred subcarriers received. This allows the delay to be reduced to a single symbol time period.

[0247] Other Aspects According to one embodiment, which may be combined with any other embodiment or may be implemented independently, an alternative solution for determining the angle between two UEs, for example useful in a remote control / TV scenario, requires the anchor UE to transmit sidelink synchronization signal blocks (SSSBs) through 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, a TV is embedded with an anchor UE equipped with an antenna featuring five beams: beam 1 perpendicular to the plane of the TV, beam 2 at 45 degrees upwards, beam 3 at 45 degrees downwards, beam 4 at 45 degrees leftwards, and beam 5 at 45 degrees rightwards. The UE can measure the change in signal strength of the anchor UE's SSSBs while the user is, for example, pressing a button. The change in the received signal strength of the SSSBs is used to obtain, for example, in which direction the user is moving the UE. It is noted that in this case, when the user presses a button on the UE, a request is triggered over the PC5 interface to transmit a synchronization or positioning signal, in this case the SSSB. The measurements are sent back from the UE to the anchor UE over the PC5 interface.

[0248] In one embodiment, which may be combined with any of the previous embodiments or implemented independently, the UE may request the anchor UE to transmit positioning signals temporarily. The reason is that existing PRS signals transmitted by base stations follow a low-frequency periodic pattern. However, many ranging scenarios require transmitting PRS signals at high frequencies for a short period of time, such as the above example of a remote control (UE) and a TV (anchor UE). In this case, the UE sends a resource scheduling request to the anchor UE via the PC5 interface to request transmission of positioning signals. The (lead) anchor UE performs resource allocation and coordinates the resource allocation with surrounding anchor UEs. For example, the anchor UE selects the PRS identifier of the anchor UE in such a way that it does not cause interference.

[0249] Process for ranging-based positioning services - Patents.com Figure 7 shows a schematic signaling and processing diagram of a ranging-based positioning service summarizing several operation options according to the above embodiment. In this diagram, the information exchange and its direction are indicated by corresponding arrows, the processing steps are shown in respective blocks, and time progresses from top to bottom in Figure 7. The locations where processing steps take place, 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 are performed multiple times for improved accuracy or continuous ranging-based positioning.

[0250] In an initial configuration step S701, the CN configures the anchor UE (A-UE) as such, which configuration includes transferring control information for configuring, for example, discovery parameters, ranging constellation identifiers, positioning signals and parameters, and / or positioning techniques. The anchor UEs are als...

Claims

1. 1. An apparatus for obtaining a location estimate for a target mobile device in a wireless network, the apparatus comprising: requesting ranging services from a ranging constellation formed by one or more ranging capable anchor devices of the wireless network, the ranging constellation acting as a proxy for positioning services provided in a geographic area; receiving at least one response message from the ranging constellation; performing range or location estimation or ranging measurements based on the at least one response message; and calculating a location of the target mobile device based on the range or location estimate or the ranging measurements, or transferring results of the range or location estimate or the ranging measurements to the ranging constellation to support the positioning services; An apparatus for performing the above.

2. 1. An apparatus for obtaining a location estimate for a target mobile device in a wireless network, the apparatus comprising: requesting ranging services from a ranging constellation formed by one or more ranging capable anchor devices of the wireless network, the ranging constellation acting as a proxy for positioning services provided in a geographic area; transmitting a ranging reference signal that can be received by at least one anchor device of the ranging constellation; receiving at least one response message from the ranging constellation; An apparatus for performing the above.

3. The apparatus of claim 2 , wherein the ranging reference signal enables anchor devices of the ranging constellation to perform ranging measurements on the ranging reference signal and calculate distance, angle, or location estimates.

4. The apparatus of claim 2 or 3, wherein the response message includes an indication of location information associated with the target mobile device.

5. The location information indication is the calculated distance of the target mobile device or an indication of the calculated distance; the calculated angle of the target mobile device or an indication of the calculated angle; or The calculated location of the target mobile device or an indication of the calculated location. The apparatus of claim 4 , comprising at least one of:

6. The device of claim 2 , wherein the device performs range or location estimation or ranging measurements based on the at least one response message.

7. The device of claim 1 or 6, wherein the device performs the range or location estimation or the ranging measurements based on discovery messages or carrier phase based ranging or positioning techniques.

8. 8. The apparatus of claim 7, wherein the apparatus transmits a positioning signal to the target mobile device or the anchor device by using a predetermined carrier signal, counts carrier cycles of the carrier signal until a response is received from the target mobile device or the anchor device, and determines a distance to the target mobile device or the anchor device based on the counted number of carrier cycles.

9. The apparatus of claim 1 , wherein the apparatus initiates self-configuration of a ranging capable anchor device.

10. The apparatus of claim 1 , wherein the apparatus is configured to switch from determining location coordinates of the target mobile device by a location service to determining location coordinates by the ranging constellation based on ranging measurements.

11. The apparatus of claim 1 , wherein the apparatus obtains location coordinates of the target mobile device from anchor devices of the ranging constellation, the location coordinates being determined by using a set of ranging measurements.

12. The apparatus of claim 1 , wherein the apparatus performs ranging or sidelink based positioning between the target mobile device and one or more anchor devices or between anchor devices of the ranging constellation.

13. 13. The apparatus of claim 1, wherein the apparatus performs at least one of: sending an identifier to the target mobile device or another ranging capable anchor device used to obtain location coordinates from a location service or database; providing authorization credentials to the target mobile device or other anchor device; providing an authorization message or credentials to the location service or database; and granting permission for the obtaining by providing consent within a subscription or through a network publishing feature.

14. The apparatus of claim 1 , wherein the apparatus indicates a number of anchor devices, a set of identifiers of the number of anchor devices, and / or a constellation identifier as part of at least one message for requesting a ranging session.

15. The apparatus of claim 1 , wherein the apparatus stores a list of approved constellation identifiers and / or ranging capable anchor devices selectable for the ranging service.

16. 16. The apparatus of claim 1, further comprising: a device configured to determine whether to request the ranging service or to determine which constellation or set of ranging capable anchor devices to select / connect to for the ranging service, the device storing at least one policy specifying a minimum number of anchor devices and / or requirements regarding capabilities and / or characteristics of the anchor devices.

17. 17. The apparatus of claim 1, wherein the apparatus is configured by a management entity or the apparatus itself is configured to switch on ranging services upon entering the geographic area or upon the target mobile device entering the geographic area.

18. 18. The apparatus of claim 1, wherein the apparatus uses signal quality or distance measurement results to determine whether to initiate the ranging service and determines that the target mobile device is sufficiently close and / or has line of sight with at least one of the ranging capable anchor devices.

19. 19. The apparatus of claim 1 , wherein the apparatus corrects the range or location estimate or the ranging measurement for a length, position, and / or orientation of at least one antenna used to perform the ranging measurement.

20. A mobile communication or access device for a wireless network comprising an apparatus according to any one of claims 1 to 19.

21. 21. The device of claim 20, in response to receiving configuration parameters or desired parameter values ​​to be used that conflict with configuration parameters received from a management entity having a higher priority, discards the ranging request, measurement results, and / or calculated distances and / or angles, generates an error message, requests an update of configuration parameters, or requests an exception from the management entity having the higher priority.

22. 21. A system comprising at least one device according to claim 20, wherein the positioning service is performed by a wireless access device or by a core network of the wireless network, and anchor devices forming the ranging constellation and participating in the requested ranging service transmit and / or receive configuration parameters between the wireless access device or the core network.

23. 23. The system of claim 22, wherein the wireless access device or the core network controls at least two of the devices to initiate a ranging session without a discovery phase, and the wireless access device or the core network provides configuration parameters so that each of the at least two devices knows how to perform the requested ranging service.

24. 23. The system of claim 22, wherein the ranging capable anchor devices of the ranging constellation are provided with a specific relay service code or service identifier that enables other ranging capable devices that are part of the ranging constellation, that are in the vicinity of the ranging constellation, and / or that are capable of ranging and / or location services, to access location and / or ranging services via a sidelink connection based on the specific relay service code or service identifier.

25. 1. A method for obtaining a location estimate for a target mobile device in a wireless network, the method comprising: requesting ranging services from a ranging constellation formed by one or more ranging capable anchor devices of the wireless network; receiving at least one response message from the ranging constellation; performing range or location estimation or ranging measurements based on the at least one response message; calculating the location of the target mobile device based on the range or location estimate or the ranging measurements, or transferring the range or location estimate or the ranging measurements to the ranging constellation to support positioning services; The method comprising:

26. 1. A method for obtaining a location estimate for a target mobile device in a wireless network, the method comprising: requesting ranging services from a ranging constellation formed by one or more ranging capable anchor devices of the wireless network, the ranging constellation acting as a proxy for positioning services provided in a geographical area; transmitting a ranging reference signal that can be received by at least one anchor device of the ranging constellation; receiving at least one response message from the ranging constellation; The method comprising:

27. A computer program comprising code means for producing the steps of the method according to claim 25 or claim 26 when said computer program is executed on a computing device.

28. 1. A method for an apparatus supporting ranging, the method comprising: determining, by the device, whether the device can act as an anchor device based on a set of criteria; said device performing a series of measurements on the received RF signals to determine or obtain a location of said device; determining by the device whether its location is sufficiently stable and / or whether the device is within the coverage of an access device according to the set of policies / criteria; the device starting to operate as an anchor device and / or starting a procedure for requesting to become an anchor device and / or for being configured as an anchor device based on at least the determination of the previous step; The method comprising:

29. 30. The method of claim 28, wherein the device ceases operating as an anchor device upon determining that a predetermined number of other anchor devices are present in the vicinity of the device.

30. 30. The method of claim 28 or 29, wherein the device stops operating as an anchor device when it determines that the coverage of location services is sufficient according to a location quality threshold at the device's current location.

31. 1. An apparatus supporting ranging, comprising: Communication unit and a processor unit coupled to the memory unit; The memory unit comprises: determining whether the device can act 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 obtain a location of the device; determining by the device whether its location is sufficiently stable and / or whether the device is within the coverage of an access device according to the set of policies / criteria; the device starting to operate as an anchor device and / or starting a procedure for requesting to become an anchor device and / or for being configured as an anchor device based on at least the determination of the previous step. An apparatus comprising instructions for carrying out the steps of:

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