Device positioning

Abstract

According to an embodiment aspect of the present invention, there is provided an apparatus, such as a user equipment, configured to receive from a wireless network node or autonomously determine a sidelink positioning reference signal configuration comprising a constraint set, the constraint set comprising at least one constraint, each of the at least one constraint being based on at least one of a location of the device, a time of day, a duration, radio measurements, physical properties of the device's surroundings, a motion state of the device, and a connection status of the device to a network; determine whether the at least one constraint in the constraint set is satisfied; and in response to the at least one constraint in the constraint set being satisfied, transmit a first sidelink positioning reference signal to a mobile device and / or receive a second sidelink positioning reference signal from the mobile device.

Description

[Technical Field]

[0001] The present disclosure relates to positioning of wireless communication devices. [Background technology]

[0002] Determining the location of wireless communication nodes enables many different use cases, such as facilitating autonomous driving, locating distress signals, finding missing people, predicting network load, and managing radio resources based on user distribution.

[0003] The position of a user equipment (UE), user device, terminal device, or other mobile device may be determined using several different methods. For example, satellite positioning, network-assisted positioning, and multilateration may be used individually or together to derive an estimate of the UE's position.

[0004] Direct communication between UEs may be referred to as device-to-device D2D or sidelink communication. In direct communication, two UEs exchange information or signals directly, in the sense that energy transmitted from the first UE is received by the second UE, thereby preventing the energy from being retransmitted by another node, e.g., a base station, along the way. In other words, D2D and sidelink communication occurs directly between UEs, without going through a base station or other radio node. Sidelink resource allocation modes can be so-called Mode 1, in which sidelink resource allocation is provided by the network, or Mode 2, in which the UE determines sidelink transmission resources from a sidelink resource pool. In Mode 2, the UE may autonomously select sidelink resources from one or more resource pools provided by access node system information via dedicated signaling when in access node coverage or by preconfiguration when out of access node coverage.

[0005] These sidelink services can be utilized in a variety of scenarios, from direct vehicle-to-vehicle communications (vehicle-to-vehicle, vehicle-to-all, cellular vehicle-to-all) to industrial automation with Ultra-Reliable Low-Latency Communications (URLLC) for mission- and business-critical applications. Sidelink connections can also be used to enhance customer experience in gaming and entertainment services using augmented reality / virtual reality / mixed reality, for example, by replacing ultra-wideband, Bluetooth, or Wi-Fi links. The sidelink air interface can also be used in multi-hop relays to provide coverage extension. Sidelink services can also include services related to managing connections with access nodes. Summary of the Invention

[0006] According to some aspects, the subject matter of the independent claims is provided. Some embodiments are defined in the dependent claims. The scope of protection sought for various embodiments of the invention is defined by the independent claims. If any, embodiments, examples, and features described herein that do not fall within the scope of the independent claims should be interpreted as examples that are helpful in understanding various embodiments of the invention.

[0007] According to a first aspect of the present disclosure, there is provided an apparatus comprising at least one processing core and at least one memory containing computer program code that, together with the at least one processing core, causes the apparatus to at least: receive from a wireless network node or autonomously determine a sidelink positioning reference signal configuration comprising a constraint set, the constraint set comprising at least one constraint, each of the at least one constraint being based on at least one of a device's location, a time of day, a duration, radio measurements, physical characteristics of the device's surroundings, a motion state of the device, and a connection status of the device to a network; determine whether the at least one constraint in the constraint set is satisfied; and transmit a first sidelink positioning reference signal to a mobile device and / or receive a second sidelink positioning reference signal from the mobile device in response to the at least one constraint in the constraint set being satisfied.

[0008] According to a second aspect of the present disclosure, there is provided an apparatus comprising at least one processing core and at least one memory containing computer program code, the at least one memory and the computer program code, together with the at least one processing core, causing the apparatus to at least: define a first mobile device as a target user equipment and at least one second mobile device as an anchor user equipment; transmit to each defined anchor user equipment a sidelink positioning reference signal configuration comprising a set of constraints, the set of constraints comprising at least one constraint, each of the at least one constraint being based on at least one of a location of the anchor user equipment, a time of day, a duration, radio measurements, physical characteristics of the anchor user equipment's surroundings, a movement state of the anchor user equipment, and a connection status of the anchor user equipment to a network; and participate in determining a location of the target user equipment based at least in part on results of measurements of the sidelink positioning reference signal at the target user equipment and the anchor user equipment.

[0009] According to a third aspect of the present disclosure, there is provided a method comprising: receiving at a device from a wireless network node or autonomously determining at the device a sidelink positioning reference signal configuration comprising a constraint set, the constraint set comprising at least one constraint, each of the at least one constraint being based on at least one of a location of the device, a time of day, a duration, radio measurements, physical characteristics of the device's surroundings, a motion state of the device, and a connection status of the device to a network; determining at the device whether the at least one constraint in the constraint set is satisfied; and transmitting a first sidelink positioning reference signal from the device to a mobile device and / or receiving at the device a second sidelink positioning reference signal from the mobile device in response to the at least one constraint in the constraint set being satisfied.

[0010] According to a fourth aspect of the present disclosure, there is provided a method, the method comprising: defining a first mobile device as a target user equipment and at least one second mobile device as an anchor user equipment; transmitting to each defined anchor user equipment a sidelink positioning reference signal configuration comprising a set of constraints, the set of constraints comprising at least one constraint, each of the at least one constraint being based on at least one of a location of the anchor user equipment, a time of day, a duration, radio measurements, physical characteristics of the anchor user equipment's surroundings, a movement state of the anchor user equipment, and a connection status of the anchor user equipment to a network; and participating in determining a location of the target user equipment based at least in part on results of measurements of the sidelink positioning reference signal at the target user equipment and the anchor user equipment.

[0011] According to a fifth aspect of the present disclosure, there is provided an apparatus, comprising: means for receiving at the apparatus from a wireless network node or autonomously determining at the apparatus a sidelink positioning reference signal configuration comprising a constraint set, the constraint set comprising at least one constraint, each of the at least one constraint being based on at least one of a location of the apparatus, a time of day, a duration, radio measurements, physical characteristics of the device's surroundings, a movement state of the device, and a connection status of the device to a network; determining at the apparatus whether the at least one constraint in the constraint set is satisfied; and transmitting a first sidelink positioning reference signal from the apparatus to a mobile device and / or receiving at the apparatus a second sidelink positioning reference signal from the mobile device in response to the at least one constraint in the constraint set being satisfied.

[0012] According to a sixth aspect of the present disclosure, an apparatus is provided, comprising means for defining a first mobile device as a target user equipment and at least one second mobile device as an anchor user equipment; transmitting to each defined anchor user equipment a sidelink positioning reference signal configuration comprising a set of constraints, the set of constraints comprising at least one constraint, each of the at least one constraint being based on at least one of a location of the anchor user equipment, a time of day, a duration, radio measurements, physical characteristics of the anchor user equipment's surroundings, a movement state of the anchor user equipment, and a connection status of the anchor user equipment to a network; and participating in determining a location of the target user equipment based at least in part on results of measurements of the sidelink positioning reference signal at the target user equipment and the anchor user equipment.

[0013] According to a seventh aspect of the present disclosure, there is provided a non-transitory computer-readable medium storing a set of computer-readable instructions that, when executed by at least one processor, cause a device to at least: receive from a wireless network node or autonomously determine a sidelink positioning reference signal configuration comprising a constraint set, the constraint set comprising at least one constraint, each of the at least one constraint being based on at least one of: a location of the device, a time of day, a duration, radio measurements, physical characteristics of the device's surroundings, a motion state of the device, and a connection status of the device to a network; determine whether the at least one constraint in the constraint set is satisfied; and transmit a first sidelink positioning reference signal to a mobile device and / or receive a second sidelink positioning reference signal from the mobile device in response to the at least one constraint in the constraint set being satisfied.

[0014] According to an eighth aspect of the present disclosure, a non-transitory computer-readable medium is provided, the non-transitory computer-readable medium storing a set of computer-readable instructions that, when executed by at least one processor, cause an apparatus to at least: define a first mobile device as a target user equipment and at least one second mobile device as an anchor user equipment; transmit to each defined anchor user equipment a sidelink positioning reference signal configuration comprising a set of constraints, the set of constraints comprising at least one constraint, each of the at least one constraint being based on at least one of a location of the anchor user equipment, a time of day, a duration, radio measurements, physical characteristics of the anchor user equipment's surroundings, a motion state of the anchor user equipment, and a connection status of the anchor user equipment to a network; and participate in determining a location of the target user equipment based at least in part on results of measurements of the sidelink positioning reference signal at the target user equipment and the anchor user equipment.

[0015] According to a ninth aspect of the present disclosure, there is provided a computer program that, when executed, causes a device to at least: receive from a wireless network node or autonomously determine a sidelink positioning reference signal configuration comprising a constraint set, the constraint set comprising at least one constraint, each of the at least one constraint being based on at least one of a location of the device, a time of day, a duration, radio measurements, physical characteristics of the device's surroundings, a motion state of the device, and a connection status of the device to a network; determine whether the at least one constraint in the constraint set is satisfied; and transmit a first sidelink positioning reference signal to a mobile device and / or receive a second sidelink positioning reference signal from the mobile device in response to the at least one constraint in the constraint set being satisfied.

[0016] According to a tenth aspect of the present disclosure, there is provided a computer program that, when executed, causes an apparatus to: define at least a first mobile device as a target user equipment and at least one second mobile device as an anchor user equipment; transmit to each defined anchor user equipment a sidelink positioning reference signal configuration comprising a set of constraints, the set of constraints comprising at least one constraint, each of the at least one constraint being based on at least one of a location of the anchor user equipment, a time of day, a duration, radio measurements, physical characteristics of the anchor user equipment's surroundings, a movement state of the anchor user equipment, and a connection status of the anchor user equipment to a network; and participate in determining a location of the target user equipment based at least in part on results of measurements of the sidelink positioning reference signal at the target user equipment and the anchor user equipment. [Brief explanation of the drawings]

[0017] [Figure 1]FIG. 1 is a diagram illustrating an example system in accordance with at least some embodiments of the present invention. [Figure 2] FIG. 2 is a diagram illustrating an example system in accordance with at least some embodiments of the present invention. [Figure 3A] FIG. 3A illustrates an embodiment of a vehicle in accordance with at least some embodiments of the present invention. [Figure 3B] FIG. 3B is a diagram illustrating an embodiment of a vehicle in accordance with at least some embodiments of the present invention. [Figure 4] FIG. 4 is a diagram illustrating an example system in accordance with at least some embodiments of the present invention. [Figure 5] FIG. 5 is a diagram illustrating an example device capable of supporting at least some embodiments of the present invention. [Figure 6] FIG. 6 is a diagram illustrating signaling in accordance with at least some embodiments of the present invention. [Figure 7] FIG. 7 is a flow diagram of a method in accordance with at least some embodiments of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0018] This disclosure describes methods for increasing the usefulness of sidelink positioning reference signals by controlling when and under what circumstances sidelink positioning reference signals are transmitted and received by UEs to facilitate sidelink-enhanced positioning of mobile devices, thereby improving positioning accuracy and avoiding unnecessary transmission of sidelink positioning reference signals that consume energy and cause interference in system spectrum resources.

[0019] A user device exemplifies one type of device to which resources on the air interface are assigned and designated. Therefore, any functionality described herein with respect to a user device may be implemented in a corresponding device, such as a relay node. An example of such a relay node is a Layer 3 relay (self-backhaul relay) to a base station. The 5G specifications define two relay modes: out-of-band relay, in which the same or different carriers can be defined for the access link and the backhaul link, and in-band relay, in which the same carrier frequency or radio resources are used for both the access link and the backhaul link. In-band relay may be considered the baseline relay scenario. A relay node is called an integrated access and backhaul (IAB) node. A relay node may support multiple relay hops. The operation of IAB assumes a so-called split architecture with a central unit (CU) and multiple distributed units (DU). An IAB node includes two distinct functions: a DU portion of the IAB node that facilitates gNB (access node) functionality in relay cells, i.e., acts as the access link, and a mobile termination (MT) portion of the IAB node that facilitates backhaul connectivity. The donor node (DU portion) communicates with the MT portion of the IAB node and has a wired connection to the CU, which also has a connection to the core network. In a multi-hop scenario, the MT portion (child IAB node) communicates with the DU portion of the parent IAB node.

[0020] A user device typically refers to portable computing devices such as wireless mobile communication devices that operate with or without a subscriber identity module (SIM), including, but not limited to, the following types of devices: mobile stations (mobile phones), smartphones, personal digital assistants (PDAs), handsets, devices using wireless modems (such as alarm devices or measurement devices), laptops and / or touchscreen computers, tablets, game consoles, notebooks, and multimedia devices. It should be understood that a user device may be almost exclusively an uplink-only device, an example of which is a camera or video camera that loads images or video clips onto a network. A user device may also be a device capable of operating in an Internet of Things (IoT) network, a scenario in which objects are provided with the ability to transfer data over a network without the need for human-to-human or human-to-computer interaction. A user device may utilize cloud computing or storage. In some applications, a user device comprises a small, portable device with wireless components (such as a watch, earphones, or glasses), and computations are performed in the cloud. A user device (or, in some embodiments, a Layer 3 relay node) is configured to perform one or more of the user equipment functions. A user device may be called a subscriber unit, a mobile station, a remote terminal, an access terminal, a user terminal, or user equipment (UE), to name just a few names or devices.

[0021] The various techniques described herein may also be applied to cyber-physical systems (CPS), which are systems of cooperating computational elements that control physical entities. CPS may enable the implementation and utilization of a large number of interconnected devices (sensors, actuators, processor microcontrollers, etc.) embedded in physical objects at different locations. Mobile cyber-physical systems, in which the physical system in question has inherent mobility, are a subcategory of cyber-physical systems. Examples of mobile physical systems include mobile robots and electronic devices carried by humans or animals.

[0022] Additionally, although an apparatus is depicted as a single entity, different units, processors and / or memory units may be implemented.

[0023] Depending on service needs, use cases, and / or available spectrum, 5G enables the use of multiple-input, multiple-output (MIMO) antennas, many more base stations or nodes than LTE, and a so-called small cell concept that includes macro sites operating in conjunction with smaller stations and employing various radio technologies. 5G mobile communications will support a wide range of use cases and related applications, such as video streaming, augmented reality, various data sharing techniques, and various forms of machine-type applications. 5G is expected to have multiple air interfaces, namely cmWave and mmWave below 6 GHz, and also be able to integrate with existing legacy radio access technology RATs, such as Long Term Evolution (LTE). Integration with LTE, at least in the early stages, may be implemented as a system in which macro coverage is provided by LTE and 5G air interface access is provided by small cells via aggregation to LTE. In other words, 5G is planned to support both inter-RAT interoperability (e.g., LTE-5G) and inter-RI interoperability (interoperability between air interfaces such as cmWave below 6 GHz, cmWave below 6 GHz to mmWave, etc.). One of the concepts considered for use in 5G networks is network slicing, which allows the creation of multiple independent and dedicated virtual sub-networks (network instances) within the same infrastructure to run services with different requirements in terms of latency, reliability, throughput, and mobility.

[0024] The current architecture of LTE networks is fully distributed over the air and typically fully centralized in the core network. Low-latency applications and services in 5G require content to be closer to the air, leading to local breakout and multi-access edge computing (MEC). 5G enables analytics and knowledge generation at the source of data. This approach must leverage resources that may not be continuously connected to the network, such as laptops, smartphones, tablets, and sensors. MEC provides a distributed computing environment for application and service hosting. It also has the ability to store and process content closer to cellular subscribers for faster response times. Edge computing covers a wide range of technologies such as wireless sensor networks, mobile data acquisition, mobile signature analysis, collaborative distributed peer-to-peer ad-hoc networking and processing (which can also be categorized as local cloud / fog computing and grid / mesh computing), dew computing, mobile edge computing, cloudlets, distributed data storage and retrieval, autonomous self-healing networks, remote cloud services, augmented and virtual reality, data caching, Internet of Things (massive connectivity and / or latency critical), and critical communications (autonomous vehicles, road safety, real-time analytics, time-critical control, medical applications).

[0025] The communication system may also communicate with or use services provided by other networks, such as the public switched telephone network or the Internet. The communication network may also support the use of cloud services, e.g., at least some of the core network operations may be performed as cloud services. The communication system may comprise a central control entity, etc., that provides facilities for networks of different operators to cooperate, e.g., in spectrum sharing.

[0026] Edge clouds can be introduced into radio access networks (RANs) by utilizing network function virtualization (NFV) and software-defined networking (SDN). The use of edge clouds can comprise access node operations that are at least partially performed in a server, host, or node operatively coupled to a remote radio head or base station that comprises a radio portion. Node operations can be distributed among multiple servers, nodes, or hosts. The application of a Cloud RAN architecture can allow RAN real-time functions to be performed on the RAN side in distributed units and non-real-time functions to be performed in a centralized manner in a centralized unit.

[0027] It should also be understood that the distribution of functionality between core network operations and base station operations may differ from that of LTE, or may even not exist. Some other technological advances that will likely be used are big data and all-IP, which could change the way networks are built and managed. 5G networks, also known as new radio NR, are designed to support multiple tiers, where MEC servers can be located between the core and base stations or Node Bs, also referred to as gNBs. It should be understood that MEC is equally applicable in 4G networks.

[0028] 5G may also utilize satellite communications to enhance or complement 5G service coverage, for example, by providing backhaul. Possible use cases are providing service continuity to machine-to-machine (M2M) or Internet of Things (IoT) devices, or passengers on board vehicles, or ensuring service availability for critical communications and future rail, maritime, and / or aviation communications. Satellite communications may utilize geostationary Earth orbit (GEO) satellite systems, but also low Earth orbit (LEO) satellite systems, especially megaconstellations (systems in which hundreds of (nano)satellites are deployed). Each satellite in a megaconstellation may cover multiple satellite-enabled network entities, creating ground cells. Ground cells may be created via terrestrial relay nodes or by gNBs located on the ground or within the satellites.

[0029] The 6G architecture is targeted to enable easy integration of everything from networks of networks, collaborative communications and sensing, non-terrestrial networks, and terrestrial communications. 6G systems are envisioned to encompass local and distributed computing capabilities, where virtualized network functions, as well as machine learning algorithms, can be distributed across core and edge computing resources. Far-edge computing, where computing resources are pushed to the very edge of the network, will be part of a distributed computing environment, for example, in a "zero latency" scenario. 5G systems may also apply such capabilities. More generally, actual (wireless) communication systems are envisioned to consist of one or more computer programs running within a programmable infrastructure, such as general-purpose computing entities (servers, processors, etc.).

[0030] As those skilled in the art will appreciate, the systems described herein are merely some examples of a wireless access system. In practice, the system may include multiple user equipments and (e / g) Node Bs. A user device may have access to multiple wireless cells, and the system may also include other devices, such as physical layer relay nodes or other network elements. At least one of the (e / g) Node Bs may be a home (e / g) Node B. In addition, a geographic area of ​​a wireless communication system may be provided with not only multiple wireless cells but also multiple different types of wireless cells. A wireless cell may be a macrocell (or umbrella cell), which is a large cell typically having a diameter of up to tens of kilometers, or a smaller cell, such as a microcell, femtocell, or picocell. The base station in FIG. 1 may provide any of these types of cells. A cellular wireless system may be implemented as a multi-tier network including several types of cells. Typically, in a multi-tier network, one access node provides one or more cells of one type, and therefore multiple (e / g) Node Bs are required to provide such a network structure.

[0031] 1 illustrates an example system in accordance with at least some embodiments of the present invention. Illustrated is an urban scenario in which roads are bounded by buildings 101, 102, 103, and 104. UEs 110, 120, and 130 are located on the roads, and UE 110 is to be located. The UE to be located is referred to herein as the target UE.

[0032] The network may determine that using base stations 150, 160 to locate the target UE 110 may produce results that are not sufficiently accurate. Reasons for this may include the target UE 110 not being communicatively connected to a sufficient number of base stations or other wireless network nodes to derive an accurate position estimate. For example, this may be the case when the target UE is near the edge of cellular coverage and / or when buildings or other objects obstruct the radio path to and from the target UE. The network may decide to use sidelink positioning reference signals to assist in locating the target UE 110, e.g., at least in part, in response to determining that locating the target UE 110 using only base stations is not sufficiently accurate. Using sidelink positioning reference signals improves UE positioning accuracy by increasing the amount of information available in deriving a position estimate for the target UE. For example, if the location of an assisting UE, known as an anchor UE, is known, measuring the round-trip time to the UE being located provides very useful information for reducing positioning inaccuracies. A UE may typically perform measurements on sidelink position reference signals, e.g., based on time, angle of arrival, received power, and / or received phase, to assist in estimating the location of a target UE. Results of such measurements may be reported to the network, which may derive a location estimate. The anchor UE's location estimate may be used in deriving a location estimate for the target UE. Measurements and location estimation may be performed when the terminal device is in a low activity mode, such as idle mode or inactive mode, and searching for an access node to access, or when the terminal device is performing beam reselection with a base station in connected mode. Idle mode, inactive mode, and connected mode may refer to Radio Resource Control (RRC) connected idle mode, inactive mode, and connected mode, respectively, in the 3rd Generation Partnership Project (3GPP) specifications.

[0033] In particular, the network may select UEs to participate in the sidelink enhanced positioning process. Such UEs are referred to herein as anchor UEs and are UEs 120 and 130 in FIG. 1 . As described in more detail below, selecting an anchor UE may be based at least in part on its location, its identifiable accuracy, and / or its state of motion or known trajectory. In some embodiments, characteristics of the potential anchor UE's physical surroundings are also used in selecting the anchor UE. For example, a UE located on high ground may be a good candidate to serve as an anchor UE because its sidelink signals can be more easily received by other UEs. In particular, the network may select such UEs as anchor UEs capable of transmitting sidelink positioning reference signals to the target UE 110. However, they do not necessarily need to be able to immediately transmit sidelink positioning reference signals to the target UE 110.

[0034] As can be seen in FIG. 1 , anchor UEs 120 and 130 are blocked from a direct line-of-sight LOS radio path to target UE 110 by buildings 101 and 102, respectively. However, as schematically shown in FIG. 1 , the anchor UEs are moving, with anchor UE 120 moving in a direction indicated by velocity vector 120v and anchor UE 130 moving in a direction indicated by velocity vector 130v. In particular, anchor UE 120 will, after a while, be at location 120t where LOS is available to target UE 110. Similarly, anchor UE 130 will, after a while, be at location 130t where LOS is available to target UE 110. Because there may be many potential anchor UEs on a road, the network may select anchor UEs from among the potential anchor UEs such that the anchor UEs are simultaneously at locations 120t and 130t, respectively.

[0035] FIG. 2 illustrates an example system according to at least some embodiments of the present invention. Like numbers refer to similar components as in FIG. 1. In particular, FIG. 2 illustrates the system of FIG. 1 after some time has passed and anchor UEs 120 and 130 are at their planned locations 120t and 130t, respectively, as discussed above. Both anchor UEs 120 and 130 have line-of-sight to the target UE and may exchange sidelink positioning reference signals 120x and 130x with the target UE 110. If the UEs have beamforming capabilities, they may transmit sidelink positioning reference signals in appropriate directions that may be specified in a sidelink positioning reference signal configuration received from the network. Similarly, they may receive reference signals from appropriate directions that may be defined in a configuration received from the network. In other words, the network may configure anchor UEs 120 and 130 with location coordinates and / or time instants at which each anchor UE transmits and / or receives a sidelink positioning reference signal when the UEs are sufficiently close in the spatial and / or temporal domains, respectively. Similarly, the target UE 110 is configured to receive / transmit sidelink positioning reference signals to / from the anchor UE 120, 130 only at configured times, which may be a period of time having a start time and an end time.

[0036] Both the anchor UE and the target UE may both receive and transmit sidelink positioning reference signals. Alternatively, only the target UE transmits sidelink positioning reference signals. As yet another option, only the anchor UE transmits sidelink positioning reference signals. While Figures 1 and 2 illustrate the case with two anchor UEs, this is merely an example; using a single anchor UE would already improve positioning accuracy by providing more information to derive a position estimate for the target UE 110. Also, three or more anchor UEs may be used if appropriate and if suitable candidate UEs are available. Because participating in sidelink enhanced positioning consumes some energy at the anchor UE, it is neither desirable nor useful to use more anchor UEs than necessary. A UE that receives a sidelink positioning reference signal may report the results of reception to the network.

[0037] Thus, overall, the transmission and / or reception of sidelink positioning reference signals by the anchor or target UEs is configured to occur at specific locations, times, and / or directions. Furthermore, this transmission and / or reception may be configured to occur in response to the occurrence of an event or the satisfaction of environmental constraints. That is, the UE may be configured to transmit / receive sidelink positioning reference signals only at specific locations and / or times and / or in specific directions. This approach allows highly mobile UEs to serve as anchor UEs or as target UEs.

[0038] In addition to information describing the mobility of UEs involved in sidelink-assisted positioning, such as speed, orientation, and trajectory, radio channel conditions, such as line-of-sight conditions and interference levels, UE capabilities, such as multi-antenna / beamforming capabilities, and environmental conditions, such as road layout and surrounding buildings, can be used to determine constraints on the configuration for sidelink positioning reference signals regarding when and where to transmit / receive them. The network can transmit a sidelink positioning reference signal configuration to the anchor UE and / or target UE, and the UE will then transmit and / or receive sidelink positioning reference signals if at least one constraint in the configuration received from the network is satisfied. For example, the configuration can define the moment at which the reference signal is sent, and the UE will be able to transmit the reference signal at a specified moment after the moment the configuration is transmitted. Mobility information of both the target UE and the anchor UE can be used to compile the sidelink positioning reference signal configuration. The mobility information shared by the UE and used to compile the configuration may include its speed, absolute position (in the case of an anchor UE) or relative position, as well as information related to direction, orientation, speed, acceleration, trajectory, path, road, route, destination, arrival / departure point, and / or area. In some embodiments, physical characteristics of the UE's surroundings are defined in constraints in the configuration to trigger transmission and / or reception of sidelink positioning reference signals. For example, the physical characteristics of the surroundings may be that the UE is located high relative to its surroundings. Another example is a constraint expressed in terms of a distance to an object in a direction specified in the constraint. If the distance from the UE to the object matches, exceeds, or is shorter than the distance specified in the constraint, reception and / or transmission of sidelink positioning reference signals is triggered.

[0039] When the UE is under the coverage of the communication network, the network may determine the sidelink positioning reference signal configuration, e.g., by indicating transmission / reception of reference signals at a specific location or time, and transmit this configuration to the anchor UE and the target UE. In case of partial or out-of-coverage operation, the network may pre-configure such sidelink positioning reference signal configurations and proactively provide them to the UE. In another embodiment, this configuration can be determined autonomously by the UE, i.e., without the need for a network entity. An example of an autonomously determined configuration is a configuration in which reference signal transmission is constrained to occur in response to a line-of-sight radio path detected between the anchor UE and the target UE.

[0040] 3A and 3B illustrate a vehicular embodiment in accordance with at least some embodiments of the present invention. Like numbers indicate similar configurations to FIGS. 1 and 2. The illustrated embodiment is vehicular in the sense that the UE is in a vehicle, such as a car or train, or the UE is actually in a vehicle, such as an autonomous vehicle. Target UE 110 is moving in the same direction as anchor UE 120, in the direction indicated by velocity vector 110v. Anchor UE 130 is traveling in the opposite direction. In this case, the network can determine that the UEs in the situation of FIG. 3A are far apart, but that after a period of time, the UEs will move closer together, as illustrated in FIG. 3B.

[0041] The network may provide each of the UEs 110, 120, 130 with a sidelink positioning reference signal configuration that includes at least one constraint that enables the UE to determine when to transmit and / or receive sidelink positioning reference signals. In Figures 3A and 3B, the constraint may be based on the location, time, or location characteristics at which the sidelink positioning reference signals are transmitted. If the constraint is location-based, the constraint specifies the locations at which the sidelink positioning reference signals are transmitted and received. The locations may be specified, for example, in terms of geographic coordinates, distance to a specific location, angular relationship to a specific location with respect to the device's heading and / or orientation, geographic area, or coverage area of ​​a cell, sector, or site of a cellular communication system. The network may derive this location by predicting where the UEs are well-positioned relative to each other for sidelink positioning reference signal transmission.

[0042] If the constraint is based on time of day, the constraint may explicitly or implicitly specify the time or period at which sidelink positioning reference signals are transmitted and / or received. The network may derive this time by predicting when the UEs will be in a good position relative to each other for sidelink positioning reference signal transmission.

[0043] If the constraint is based on characteristics of the locations where the sidelink positioning reference signals are transmitted, the network may define constraints on the distance between the target UE and the anchor UE or on geographical features of locations where the UEs are expected by the network to be reasonably close to each other. As in the embodiments of Figures 1 and 2, the UE may report back to the network the results of measurements it has made on the sidelink positioning reference signals.

[0044] 1 and 2, if the UE supports directional transmission and reception, the network may specify the direction in which the sidelink positioning reference signals are transmitted and / or received. Such direction may be expressed, for example, as an absolute direction with respect to geographic north or as a relative direction with respect to the direction of device motion.

[0045] FIG. 4 illustrates an example system in accordance with at least some embodiments of the present invention. In this embodiment, a factory environment exists in which some devices have predefined trajectories. For example, large automated guided vehicles may always follow specific routes across several zones of the factory. The routes may correspond, for example, to rails installed on the ground along which these vehicles travel. In particular, anchor UE 120 follows trajectory 420, and anchor UE 430 follows trajectory 430. Meanwhile, some mobile devices, such as small robots or drones, may have unknown paths. To locate such devices, which are target UEs, such as UE 110, the network may utilize UEs with fixed paths as anchor UEs and leverage their known positions to determine when to transmit / receive sidelink positioning reference signals to locate target UE 110. In particular, the network may configure specific time periods in specific directions for transmitting / receiving sidelink positioning reference signals.

[0046] The previously known position along the trajectory 420, 430 of the anchor UE, together with measurements made by the device on sidelink positioning reference signals, helps to estimate the location of the target device. In another embodiment, a larger sized anchor UE may have even more processing power and therefore could also estimate the location information of the target UE 110 instead of a network entity by collecting sidelink positioning reference signal measurements from UEs involved in positioning.

[0047] FIG. 5 illustrates an example apparatus capable of supporting at least some embodiments of the present invention. Illustrated is device 500, which may comprise, for example, a mobile communications device, such as UE 110, 120, or 130 of the figure, or, where applicable, a suitable network node. Device 500 includes processor 510, which may comprise, for example, a single-core processor or a multi-core processor, where a single-core processor comprises one processing core and a multi-core processor comprises two or more processing cores. Processor 510 may generally comprise a control device. Processor 510 may comprise multiple processors. Processor 510 may be the control device. The processing core may comprise, for example, a Cortex-A8 processing core manufactured by ARM Holdings or a Zen processing core designed by Advanced Micro Devices, Inc. Processor 510 may comprise at least one Qualcomm Snapdragon and / or Intel Atom processor. Processor 510 may comprise at least one application-specific integrated circuit (ASIC). Processor 510 may comprise at least one field-programmable gate array (FPGA). The processor 510 may be a means for performing method steps in the device 500. The processor 510 may be configured to perform actions such as receiving, determining, transmitting, or causing to transmit, define, and participate at least in part by computer instructions.

[0048] A processor may comprise circuitry or may be configured as one or more circuitry, the one or more circuitry configured to perform steps of methods according to embodiments described herein. As used herein, the term "circuitry" may refer to one or more or all of the following: (a) a hardware-only circuit implementation, such as an implementation with only analog and / or digital circuitry; (b) a combination of hardware circuitry and software, where applicable, such as (i) a combination of analog and / or digital hardware circuitry and software / firmware, and (ii) any portion of hardware with software (including a digital signal processor, software, and memory that work together to cause a device such as a mobile phone or server to perform various functions); and (c) a hardware circuit and / or processor, such as a microprocessor or portion of a microprocessor, that requires software (e.g., firmware) to operate, but may not be present if the software is not necessary for operation.

[0049] This definition of circuitry applies to all uses of the term in this application, including any claims. As a further example, as used in this application, the term circuitry also covers a simple hardware circuit or processor (or processors), or a portion of a hardware circuit or processor, and its (or their) accompanying software and / or firmware implementation. The term circuitry also covers, for example, a baseband integrated circuit or processor integrated circuit for a mobile device, or a similar integrated circuit in a server, cellular network device, or other computing or network device, if applicable to certain claim elements.

[0050] The device 500 may include a memory 520. The memory 520 may include random access memory and / or permanent memory. The memory 520 may include at least one RAM chip. The memory 520 may include, for example, solid-state memory, magnetic memory, optical memory, and / or holographic memory. The memory 520 may be at least partially accessible to the processor 510. The memory 520 may be at least partially included in the processor 510. The memory 520 may be a means for storing information. The memory 520 may include computer instructions configured to be executed by the processor 510. If computer instructions configured to cause the processor 510 to perform a particular operation are stored in the memory 520 and the entire device 500 is configured to execute under the direction of the processor 510 using the computer instructions from the memory 520, the processor 510 and / or at least one processing core thereof may be considered to be configured to perform the particular operation. The memory 520 may be at least partially included in the processor 510. The memory 520 may be, at least in part, external to the device 500 but accessible to the device 500 .

[0051] Device 500 may comprise a transmitter 530. Device 500 may comprise a receiver 540. Transmitter 530 and receiver 540 may be configured to transmit and receive information, respectively, according to at least one cellular or non-cellular standard. Transmitter 530 may comprise multiple transmitters. Receiver 540 may comprise multiple receivers. Transmitter 530 and / or receiver 540 may be configured to operate according to, for example, the Global System for Mobile Communications (GSM) standard, the Wideband Code Division Multiple Access (WCDMA) standard, the 5G standard, the Long Term Evolution (LTE) standard, the IS-95 standard, the Wireless Local Area Network (WLAN) standard, the Ethernet standard, and / or the Worldwide Interoperability for Microwave Access (WiMAX) standard.

[0052] The device 500 may include a near field communication (NFC) transceiver 550. The NFC transceiver 550 may support at least one NFC technology, such as NFC, Bluetooth, Wibree, or a similar technology.

[0053] Device 500 may include a user interface UI 560. UI 560 may include at least one of a display, a keyboard, a touchscreen, a vibrator configured to signal a user by vibrating device 500, a speaker, and a microphone. A user may be able to operate device 500 via UI 560, for example, to set positioning parameters.

[0054] Device 500 may include or be configured to accept a user identification module 570. User identification module 570 may include, for example, a subscriber identity module (SIM) card installable in device 500. User identification module 570 may include information identifying a subscription of a user of device 500. User identification module 570 may include cryptographic information usable to verify the identity of the user of device 500 and / or to facilitate encryption of communicated information and billing of the user of device 500 for communications made via device 500.

[0055] The processor 510 may be equipped with a transmitter configured to output information from the processor 510 to other devices included in the device 500 via electrical leads internal to the device 500. Such a transmitter may comprise, for example, a serial bus transmitter configured to output information via at least one electrical lead to the memory 520 for storage. Instead of a serial bus, the transmitter may comprise a parallel bus transmitter. Similarly, the processor 510 may be equipped with a receiver configured to receive information at the processor 510 from other devices included in the device 500 via electrical leads internal to the device 500. Such a receiver may comprise, for example, a serial bus receiver configured to receive information via at least one electrical lead from the receiver 540 for processing in the processor 510. Instead of a serial bus, the receiver may comprise a parallel bus receiver.

[0056] Device 500 may include additional devices not illustrated in FIG. 5 . For example, if device 500 includes a smartphone, device 500 may include at least one digital camera. Some devices 500 may include a rear camera and a front camera, where the rear camera may be intended for digital photography and the front camera for video calling. Device 500 may include a fingerprint sensor configured to at least partially authenticate a user of device 500. In some embodiments, device 500 does not include at least one of the devices described above. For example, some devices 500 may not include NFC transceiver 550 and / or user identification module 570.

[0057] The processor 510, memory 520, transmitter 530, receiver 540, NFC transceiver 550, UI 560, and / or user identification module 570 may be interconnected in many different ways by electrical leads inside device 500. For example, each of the aforementioned devices may be individually connected to a master bus inside device 500 so that the devices can exchange information. However, those skilled in the art will appreciate that this is only one example, and depending on the embodiment, various ways of interconnecting at least two of the aforementioned devices may be selected without departing from the scope of the present invention.

[0058] 6 illustrates signaling according to at least some embodiments of the present invention. The vertical axis shows the network node performing the positioning task on the left, the anchor UEs 120 and 130 in the center, and the target UE 110 on the right. Time progresses from top to bottom. The number of anchor UEs may be different from the two illustrated.

[0059] In step 610, the network node NW determines that the UE 110 should be located, i.e., that a position estimate should be determined for the UE 110. This may be based on a positioning request, for example, from the UE 110 itself or from a network dispatcher. The node may also determine that sidelink-assisted positioning is necessary because accuracy may be insufficient without sidelink-assisted positioning. In step 620, the network node NW selects a UE other than the UE 110 to serve as the anchor UE. This selection may be based on at least one of the accuracy with which the UE can be located, the UE's mobility state, and the UE's beamforming capabilities. The network node also compiles a sidelink positioning reference signal configuration that enables the involved UEs, i.e., the target UE and the anchor UE, to decide when to transmit and / or receive sidelink positioning reference signals. As mentioned above, in some embodiments, both the anchor UE and the target UE transmit and receive these reference signals, while in other embodiments, only the anchor UE or the target UE transmits and the other UEs receive.

[0060] In steps 630, 640, and 650, the network provides sidelink positioning reference signal configurations to the participating anchor and target UEs 120, 130, and 110, respectively. In subsequent steps 660, 670, and 680, the UE monitors whether any of the constraints in these configurations are satisfied. In some embodiments, all constraints in the configurations must be satisfied before the UE can transmit and / or receive reference signals, while in other embodiments, the satisfaction of at least one of the constraints is sufficient to trigger transmission and / or reception of sidelink positioning reference signals.

[0061] The criteria in the configuration provided to the UE are designed to be met approximately simultaneously. If the criteria are met approximately simultaneously, the anchor UE 120 exchanges sidelink positioning reference signals with the target UE 110 in step 690, and the anchor UE 130 exchanges sidelink positioning reference signals with the target UE 110 in step 6100. The UE performs measurements on these reference signals, measuring parameters such as reception time, reception direction, and / or signal power level upon reception. In some embodiments, the anchor UE determines whether to transmit / receive reference signals based on the accuracy of its location information. As a result, if its location is unreliable, the anchor UE may choose to refrain from transmitting reference signals. In general, the decision to refrain from transmitting / receiving reference signals may be based on the quality of service of the anchor UE's positioning capabilities. The quality of service may be expressed, for example, in terms of latency, accuracy, or completeness.

[0062] The UE reports the results of these measurements to the network in steps 6110, 6120, 6130. The anchor UE 120, 130 may include in these reports its position at the moment the reference signals were transmitted and / or received. The network node NW derives a position estimate for the target UE 110 in step 6140. The derivation of this position estimate may take as input not only sidelink related measurements but also measurements made at the target UE 110 via one or more base stations.

[0063] Location-based constraints in the configuration may be expressed in terms of absolute or relative location coordinates (e.g., specified in terms of GPS coordinates or distance to a known location such as the current location) or confidence intervals for specified relative location coordinates; for example, how close (in terms of an offset threshold) to given coordinates the UE needs to transmit or receive a reference signal; geographic area or zone information (e.g., a rectangular area specified in terms of known coordinates or a geofence); transmission-reception points, cells, sectors, or site areas (e.g., determined by radio resource management measurements, cell / TRP identifiers, or assistance data provided by the network).

[0064] In one embodiment, sidelink positioning reference signal transmissions are triggered within an area defined by local coordinates. Here, the anchor UE radio link monitoring and / or measurement configuration is configured to determine when the UE enters or leaves a configured sidelink positioning reference signal transmission area. If radio link monitoring measurements exceed a threshold and / or if the anchor UE enters the configured area, this triggers the transmission of a reference signal. The configured location-aware reference signal transmission covers a configured area that allows the target UE to receive the reference signal. When the anchor UE enters the area, it monitors that the area is valid, and the target UE may monitor and report measurements (e.g., RSRP) to the anchor UE. In other words, in this embodiment, the area in which the sidelink positioning reference signal is transmitted is defined by criteria in the sidelink positioning reference signal configuration in terms of signal power or quality level from at least one transmitter. Examples of such transmitters include signals from base stations. For example, the criteria may define that the sidelink positioning reference signal is sent while the signal power from a first base station is within a first interval and the signal power from a second base station is within a second interval.

[0065] The time reference in the configuration may be expressed in terms of an absolute or relative time instance (e.g., specified with respect to UTC, or a subframe number, or a time relative to the current time). Relative time may be expressed, for example, with respect to a previous location of the device. For example, a time window combined with the above, with a specified start or end time / duration. Periodicity or frequency information, or a specific (set of) time / frequency resources (e.g., subframes, slots, resource blocks, resource elements, subchannels, subcarriers, bandwidth), with a specified start / end time and / or duration.

[0066] The directional reference in the configuration may be expressed in terms of an antenna panel or element, a beam, an antenna radiation pattern or beamwidth, a relative or absolute geographic direction, a relative or absolute angular information, or an angular confidence interval such as an angular direction + / - a specified number of degrees.

[0067] Event-based criteria in the configuration can be expressed in terms of motion, such as when a certain speed or acceleration is exceeded, when a certain direction is turned, when entering, leaving, or remaining within a specified area or zone, when a line-of-sight radio path to the target / anchor UE occurs, or when a non-line-of-sight radio path to the target / anchor UE is detected based on channel conditions, such as when / until sidelink channel measurements such as CBR, RSRP, RSSI, CSI, SINR, etc., and when the Doppler spread falls below / below or exceeds / exceeds a certain threshold. Measurements can also include measurements of the sidelink channel occupancy ratio (SLCR) and the sidelink channel busy ratio (SLCBR), and the UE can use this information to select a low-occupancy beam. Furthermore, radio measurements on uplink or downlink signals can also be used in the criteria, as they can connect to or disconnect from the network or a specific cell or TRP.

[0068] The Quality of Service QoS of the positioning request may be used to define the criteria in the configuration, for example, the anchor UE may be allowed to decide whether it can transmit / receive the requested SLPRS based on the QoS, e.g., based on the accuracy of its location information or energy level / status.

[0069] In another embodiment, another UE can configure the sidelink positioning reference signal configuration for the anchor UE or the target UE on behalf of the network. Similarly, the UE can perform the position estimation calculation on behalf of the network by collecting measurements.

[0070] 7 is a flow diagram of a method according to at least some embodiments of the present invention. The illustrated method steps may be performed within UE 110 or within a control device configured to control the functionality of UE 110 if installed within UE 110.

[0071] Step 710 comprises receiving, at the device from a base station node or autonomously determining, at the device, a sidelink SL positioning reference signal PRS configuration comprising a constraint set, the constraint set comprising at least one constraint, each of which is based on at least one of the device's location, time, time duration, radio measurements, physical characteristics of the device's surroundings, a motion state of the device, and a network connection status of the device. Step 720 comprises determining, at the device, whether the at least one constraint in the constraint set is satisfied. Finally, step 730 comprises transmitting a first sidelink positioning reference signal from the device to the mobile device and / or receiving, at the device, a second sidelink positioning reference signal from the mobile device in response to the at least one constraint in the constraint set being satisfied.

[0072] It is to be understood that the disclosed embodiments of the invention are not limited to the particular structures, process steps, or materials disclosed herein, but extend to equivalents thereof as recognized by those skilled in the art. It is also to be understood that the terminology applied herein is used for the purpose of describing particular embodiments only, and is not intended to be limiting.

[0073] Reference throughout this specification to one embodiment or an embodiment means that a particular feature, structure, or characteristic described in connection with that embodiment is included in at least one embodiment of the present invention. Thus, the appearances of the phrase "in one embodiment" or "in an embodiment" in various places throughout this specification do not necessarily all refer to the same embodiment. For example, when a numerical value is referred to using terms such as about or substantially, the exact numerical value is also disclosed.

[0074] As used herein, a plurality of items, structural elements, components, and / or materials may be presented in a common list for convenience. However, these lists should be construed as though each member of the list were individually identified as a separate and unique member. Accordingly, individual members of such lists should not be construed as de facto equivalents to other members of the same list solely based on presentation within a common grouping, absent a contrary indication. In addition, various embodiments and examples of the present invention may be referenced herein, along with alternatives for the various components thereof. It is understood that such embodiments, examples, and alternatives should not be construed as de facto equivalents of each other, but should be considered as separate, autonomous representations of the present invention.

[0075] Furthermore, the described features, structures, or characteristics may be combined in any suitable manner in one or more embodiments. In the foregoing description, numerous specific details are provided, such as examples of length, width, shape, etc., to provide a thorough understanding of embodiments of the invention. However, one skilled in the art will recognize that the invention can be practiced without one or more specific details, or with other methods, components, materials, etc. In some instances, well-known structures, materials, or operations are not shown or described in detail to avoid obscuring aspects of the invention.

[0076] While the foregoing examples illustrate the principles of the present invention in one or more particular applications, it will be apparent to those skilled in the art that many modifications in form, use, and details of implementation can be made without the exercise of the inventive faculty and without departing from the principles and concepts of the present invention. Accordingly, it is not intended that the present invention be limited except as by the claims which follow.

[0077] The verbs "comprise" and "include" are used in this document as open limitations which neither exclude nor require the presence of any unrecited features. Features recited in the dependent claims are mutually freely combinable unless expressly stated otherwise. Furthermore, it is to be understood that the use of "a" or "an", i.e., the singular, throughout this specification does not exclude the plural. [Industrial Applicability]

[0078] At least some embodiments of the present invention find industrial application in wireless positioning. [Explanation of symbols]

[0079] TRP Transmit / Receive Point CBR Channel Busy Radio CSI Channel State Information SINR Signal to Interference and Noise Ratio RSRP Received signal receive power RSSI Received Signal Strength Indicator UTC Coordinated Universal Time 101, 102, 103, 104 Buildings 110 Target UE 120,130 anchor UE 150,160 base stations 120t,130t position 120x, 130x Sidelink positioning reference signal 110v, 120v, 130v UE speed vector 420,430 orbit (Fig. 4) 500~570 Device structure in Figure 5 610-6140 Steps of the process illustrated in FIG. 710-730 Steps of the method of FIG.

Claims

1. 1. A user equipment comprising at least one processing core and at least one memory containing computer program code, the at least one memory and the computer program code being stored in the user equipment together with the at least one processing core ... receiving, receiving or autonomously determining from a wireless network node a sidelink positioning reference signal configuration comprising a constraint set, the constraint set comprising at least one constraint, each of the at least one constraint being based on at least one of a location of the user equipment, a time of day, a duration; determining whether the position constraints in said constraint set are satisfied; transmitting a first sidelink positioning reference signal to the mobile device and / or receiving a second sidelink positioning reference signal from the mobile device in response to the location constraints in the constraint set being satisfied; and wherein the sidelink positioning reference signal configuration further comprises an indication of a direction, absolute or relative, in which the first sidelink positioning reference signal is transmitted and / or received, and wherein the user equipment is configured to transmit the first sidelink positioning reference signal in said direction and / or receive the first sidelink positioning reference signal from said direction.

2. 2. The user equipment of claim 1, wherein at least one of the at least one constraint is based on the location of the user equipment, and the constraint based on the location of the user equipment is satisfied if the user equipment is in a location specified by the constraint.

3. 3. The user equipment of claim 2, wherein the location in the constraint is specified in terms of one or more of geographic coordinates, a distance to a particular place or object including another mobile node or network node, an angular relationship to a particular place with respect to a heading and / or orientation of the user equipment, a geographic area, or a coverage area of ​​a cell, sector or site of a cellular communication system.

4. 4. The user equipment of claim 1, wherein at least one of the at least one constraints is based on the time of day, and the constraint based on the time of day is satisfied if the current time matches the time specified in the constraint.

5. 5. The user equipment of claim 4, wherein the time in the constraint is specified in terms of one or more of an absolute or relative time of day, a time window, a periodicity, a subframe slot, a resource block, a number of subframes, a time slot, or a resource element.

6. 6. The user equipment of claim 1, wherein each of the at least one constraint is further based on at least one of radio measurements, physical characteristics of the user equipment's surroundings, a state of movement of the user equipment, and a connection status of the user equipment to a network.

7. A user equipment as claimed in any one of claims 1 to 6, wherein a further constraint is based on a motion state of the user equipment, and the constraint based on the motion state of the user equipment is satisfied if the current motion state of the user equipment matches the motion state of the user equipment specified in the constraint.

8. 1. A method comprising: receiving, receiving or determining at a user equipment from a wireless network node or autonomously at the user equipment a sidelink positioning reference signal configuration comprising a constraint set, the constraint set comprising at least one constraint, each of the at least one constraint being based on at least one of a location of the user equipment, a time of day or a duration; - determining, in said user equipment, whether at least one constraint in said constraint set is satisfied; transmitting a first sidelink positioning reference signal from the user equipment to a mobile device and / or receiving at the user equipment a second sidelink positioning reference signal from the mobile device in response to the at least one constraint in the constraint set being satisfied; wherein the sidelink positioning reference signal configuration further comprises an indication of a direction, absolute or relative, in which the first sidelink positioning reference signal is transmitted and / or received, and wherein the user equipment is configured to transmit the first sidelink positioning reference signal in said direction and / or receive the first sidelink positioning reference signal from said direction.

9. 9. The method of claim 8, wherein the sidelink positioning reference signal configuration further comprises an indication of an absolute or relative direction in which the first sidelink positioning reference signal is transmitted and / or received, the transmission of the first sidelink positioning reference signal being towards and / or the reception of the first sidelink positioning reference signal being from said direction.

10. 10. The method of claim 8 or 9, wherein at least one of the at least one constraints is based on the location of the user equipment, and the at least one constraint based on the location of the user equipment is satisfied if the user equipment is in a location specified in the constraint.

11. 11. The method of claim 10, wherein the location in the constraint is specified in terms of one or more of geographic coordinates, a distance to a particular location, an angular relationship to a particular location with respect to a heading and / or orientation of the user equipment, a geographic area, or a coverage area of ​​a cell, sector, or site of a cellular communication system.

12. 12. The method of claim 8, wherein at least one of the at least one constraints is based on the time of day, and wherein the at least one constraint based on the time of day is satisfied if a current time coincides with the time specified in the constraint.

13. 13. The method of claim 12, wherein the time in the constraint is specified in terms of one or more of an absolute or relative time of day, a time window, a periodicity, a subframe slot, a resource block, a number of subframes, a time slot, or a resource element.

14. 14. The method of claim 8, wherein at least one of the at least one constraints is based on a motion state of the user equipment, and wherein the at least one constraint based on the motion state of the user equipment is satisfied if the current motion state of the user equipment matches the motion state of the user equipment specified in the constraint.

15. A non-transitory computer-readable medium that, when executed by at least one processor, causes a user device to: receiving from a wireless network node or autonomously determining a sidelink positioning reference signal configuration comprising a constraint set, the constraint set comprising at least one constraint, each of the at least one constraint being based on at least one of a location of the user equipment, a time of day, or a duration; determining whether at least one constraint in said set of constraints is satisfied; transmitting a first sidelink positioning reference signal to a mobile device and / or receiving a second sidelink positioning reference signal from the mobile device in response to the at least one constraint in the set of constraints being satisfied; the sidelink positioning reference signal configuration further comprising an indication of a direction, absolute or relative, in which the first sidelink positioning reference signal is transmitted and / or received, and the user equipment is configured to transmit the first sidelink positioning reference signal in the direction and / or receive the first sidelink positioning reference signal from the direction.

16. A non-transitory computer-readable medium that, when executed by at least one processor, causes a network node to at least: - defining a first mobile device as a target user equipment and at least one second mobile device as an anchor user equipment; - transmitting to each defined anchor user equipment a sidelink positioning reference signal configuration comprising a set of constraints, the set of constraints comprising at least one constraint, each of the at least one constraint being based on at least one of a location of the anchor user equipment, a time of day, or a duration; a non-transitory computer-readable medium storing a set of computer-readable instructions for causing a target user equipment to participate in determining the location of the target user equipment based at least in part on results of measurements of sidelink positioning reference signals at the target user equipment and the anchor user equipment.

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