Positioning reference unit selection

Abstract

The present disclosure relates to positioning reference element selection. A method is disclosed, comprising: obtaining a first set of measurement information associated with reference signals transmitted from a set of positioning reference elements; selecting a subset of positioning reference elements from the set of positioning reference elements, wherein the selection is based at least on determining that the reference signals transmitted by each positioning reference element in the subset of positioning reference elements are measured by the same set of network nodes that measure reference signals transmitted from a target user equipment; and refining a position estimate of a target user equipment based at least on a subset of measurement information from the first set of measurement information, wherein the subset of measurement information is associated with the subset of positioning reference elements.

Description

Technical Field

[0001] The following example embodiments relate to wireless communications and positioning. Background Art

[0002] Positioning technology can be used to estimate the physical location of a device. It is desirable to improve positioning accuracy so that the location of a device can be estimated more accurately. Summary of the Invention

[0003] The scope of protection sought by various exemplary embodiments is defined by the independent claims. Exemplary embodiments and features described in this specification that do not fall within the scope of the independent claims, if any, should be interpreted as examples that aid in understanding the various embodiments.

[0004] According to one aspect, a device is provided, comprising at least one processor and at least one memory storing instructions that, when executed by the at least one processor, cause the device to at least: obtain a first set of measurement information associated with a reference signal sent from a set of positioning reference units; select a subset of positioning reference units from the set of positioning reference units, wherein the selection is based at least on determining that the reference signal sent by each positioning reference unit of the subset of positioning reference units is measured by the same set of network nodes that measure the reference signal sent from a target user equipment, wherein the subset of positioning reference units is further selected based on at least one of: a comparison of a time of flight of the reference signal sent by each positioning reference unit of the subset of positioning reference units with a time of flight of the reference signal sent from the target user equipment, or a comparison of a timing advance of each positioning reference unit of the subset of positioning reference units with a timing advance of the target user equipment; and refine a position estimate of the target user equipment based at least on a subset of measurement information from the first set of measurement information, wherein the subset of measurement information is associated with the subset of positioning reference units.

[0005] According to another aspect, a device is provided, comprising: a device for obtaining a first measurement information set associated with a reference signal sent from a set of positioning reference units; a device for selecting a subset of positioning reference units from the set of positioning reference units, wherein the selection is based at least on determining that the reference signal sent by each positioning reference unit of the subset of positioning reference units is measured by the same set of network nodes that measure the reference signal sent from a target user equipment, wherein the subset of positioning reference units is further selected based on at least one of the following: a comparison of the flight time of the reference signal sent by each positioning reference unit of the subset of positioning reference units with the flight time of the reference signal sent from the target user equipment, or a comparison of the timing advance of each positioning reference unit of the subset of positioning reference units with the timing advance of the target user equipment; and a device for refining the position estimate of the target user equipment based on at least a subset of measurement information from the first measurement information set, wherein the subset of measurement information is associated with the subset of positioning reference units.

[0006] According to another aspect, a method is provided, the method comprising: obtaining a first set of measurement information associated with a reference signal sent from a set of positioning reference units; selecting a subset of positioning reference units from the set of positioning reference units, wherein the selection is based at least on determining that the reference signal sent by each positioning reference unit of the subset of positioning reference units is measured by the same set of network nodes that measure the reference signal sent from a target user equipment, wherein the subset of positioning reference units is further selected based on at least one of: a comparison of a time of flight of the reference signal sent by each positioning reference unit of the subset of positioning reference units with a time of flight of the reference signal sent from the target user equipment, or a comparison of a timing advance of each positioning reference unit of the subset of positioning reference units with a timing advance of the target user equipment; and refining a position estimate of the target user equipment based at least on a subset of measurement information from the first measurement information set, wherein the subset of measurement information is associated with the subset of positioning reference units.

[0007] According to another aspect, a computer program is provided, the program comprising instructions that, when executed by a device, cause the device to at least perform the following: obtain a first set of measurement information associated with a reference signal sent from a set of positioning reference units; select a subset of positioning reference units from the set of positioning reference units, wherein the selection is based at least on determining that the reference signal sent by each positioning reference unit of the subset of positioning reference units is measured by the same set of network nodes that measure the reference signal sent from a target user equipment, wherein the subset of positioning reference units is further selected based on at least one of the following: a comparison of a time of flight of the reference signal sent by each positioning reference unit of the subset of positioning reference units with a time of flight of the reference signal sent from the target user equipment, or a comparison of a timing advance of each positioning reference unit of the subset of positioning reference units with a timing advance of the target user equipment; and refine a position estimate of the target user equipment based on at least a subset of measurement information from the first measurement information set, wherein the subset of measurement information is associated with the subset of positioning reference units.

[0008] According to another aspect, a computer-readable medium is provided, comprising program instructions that, when executed by an apparatus, cause the apparatus to at least perform the following: obtain a first set of measurement information associated with a reference signal sent from a set of positioning reference units; select a subset of positioning reference units from the set of positioning reference units, wherein the selection is based at least on determining that the reference signal sent by each positioning reference unit of the subset of positioning reference units is measured by the same set of network nodes that measure the reference signal sent from a target user equipment, wherein the subset of positioning reference units is further selected based on at least one of the following: a comparison of a time of flight of the reference signal sent by each positioning reference unit of the subset of positioning reference units with a time of flight of the reference signal sent from the target user equipment, or a comparison of a timing advance of each positioning reference unit of the subset of positioning reference units with a timing advance of the target user equipment; and refine a position estimate of the target user equipment based at least on a subset of measurement information from the first measurement information set, wherein the subset of measurement information is associated with the subset of positioning reference units.

[0009] According to another aspect, a non-transitory computer-readable medium is provided, comprising program instructions that, when executed by an apparatus, cause the apparatus to at least perform the following: obtain a first set of measurement information associated with a reference signal sent from a set of positioning reference units; select a subset of positioning reference units from the set of positioning reference units, wherein the selection is based at least on determining that the reference signal sent by each positioning reference unit of the subset of positioning reference units is measured by the same set of network nodes that measure the reference signal sent from a target user equipment, wherein the subset of positioning reference units is further selected based on at least one of the following: a comparison of a time of flight of the reference signal sent by each positioning reference unit of the subset of positioning reference units with a time of flight of the reference signal sent from the target user equipment, or a comparison of a timing advance of each positioning reference unit of the subset of positioning reference units with a timing advance of the target user equipment; and refine a position estimate of the target user equipment based at least on a subset of measurement information from the first measurement information set, wherein the subset of measurement information is associated with the subset of positioning reference units.

[0010] According to another aspect, a system is provided, comprising at least a location management function and a user equipment, wherein the user equipment is configured to initiate an activation procedure to activate one or more positioning reference elements for a positioning session of the user equipment, wherein the activation procedure is initiated based on at least one of: a radio resource control state of the user equipment, a number of detected network nodes, or a number of detected positioning reference elements. The location management function is configured to: obtain a first measurement information set associated with a reference signal sent from a set of positioning reference units; select a subset of positioning reference units from the set of positioning reference units, wherein the selection is based at least on determining that the reference signal sent by each positioning reference unit of the subset of positioning reference units is measured by the same set of network nodes that measure the reference signal sent from a target user equipment, wherein the subset of positioning reference units is further selected based on at least one of the following: a comparison of the flight time of the reference signal sent by each positioning reference unit of the subset of positioning reference units with the flight time of the reference signal sent from the target user equipment, or a comparison of the timing advance of each positioning reference unit of the subset of positioning reference units with the timing advance of the target user equipment; and refine the position estimate of the target user equipment based on at least a subset of measurement information from the first measurement information set, wherein the subset of measurement information is associated with the subset of positioning reference units.

[0011] According to another aspect, a system is provided, comprising at least a location management function and a user equipment. The user equipment comprises means for initiating an activation procedure to activate one or more positioning reference elements for a positioning session of the user equipment, wherein the activation procedure is initiated based on at least one of: a radio resource control state of the user equipment, a number of detected network nodes, or a number of detected positioning reference elements. The location management function comprises: a device for obtaining a first set of measurement information associated with a reference signal sent from a set of positioning reference units; a device for selecting a subset of positioning reference units from the set of positioning reference units, wherein the selection is based at least on determining that the reference signal sent by each positioning reference unit of the subset of positioning reference units is measured by the same set of network nodes that measure the reference signal sent from the target user equipment, wherein the subset of positioning reference units is further selected based on at least one of the following: a comparison of the flight time of the reference signal sent by each positioning reference unit of the subset of positioning reference units with the flight time of the reference signal sent from the target user equipment, or a comparison of the timing advance of each positioning reference unit of the subset of positioning reference units with the timing advance of the target user equipment; and a device for refining the position estimate of the target user equipment based at least on a subset of measurement information from the first measurement information set, wherein the subset of measurement information is associated with the subset of positioning reference units. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Various example embodiments will be described in more detail below with reference to the accompanying drawings, in which

[0013] Figure 1 An example of a cellular communication network is shown;

[0014] Figure 2 A positioning scenario is shown;

[0015] Figure 3 shows a flow chart according to an example embodiment;

[0016] Figure 4 shows a flow chart according to an example embodiment;

[0017] Figure 5 shows a flow chart according to an example embodiment;

[0018] Figure 6 shows a flow chart according to an example embodiment;

[0019] Figure 7 shows a flow chart according to an example embodiment;

[0020] Figure 8 shows a flow chart according to an example embodiment;

[0021] Figure 9 shows a flow chart according to an example embodiment;

[0022] Figure 10 illustrates a signaling diagram according to an example embodiment;

[0023] Figure 11 An example scenario is shown;

[0024] Figure 12 An example of an apparatus is shown;

[0025] Figure 13 An example of an apparatus is shown. DETAILED DESCRIPTION

[0026] The following embodiments are illustrative. Although the specification may refer to "one," "an," or "some" embodiments in several places in the text, this does not necessarily mean that each reference refers to the same embodiment or that a particular feature applies to only a single embodiment. Individual features of different embodiments may also be combined to provide other embodiments.

[0027] In the following example embodiments, different example embodiments will be described using radio access architectures based on Long Term Evolution Advanced (LTE Advanced, LTE-a), New Radio (NR, 5G), Beyond 5G or Sixth Generation (6G) as examples of access architectures to which the example embodiments may be applied, without, however, limiting the example embodiments to such architectures. It will be apparent to those skilled in the art that the example embodiments may also be applied to other types of communication networks with suitable means by appropriately adjusting parameters and procedures. Some examples of other choices for suitable systems may be Universal Mobile Telecommunications System (UMTS) Radio Access Network (UTRAN or E-UTRAN), Long Term Evolution (LTE, which is essentially the same as E-UTRA), Wireless Local Area Networks (WLAN or Wi-Fi), Worldwide Interoperability for Microwave Access (WiMAX), Personal Communications Service (PCS), Wideband Code Division Multiple Access (WCDMA), systems using Ultra-Wideband (UWB) technology, sensor networks, mobile ad hoc networks (manet) and Internet Protocol Multimedia Subsystem (IMS), or any combination thereof. Figure 1 An example of a simplified system architecture is depicted showing some components and functional entities which are logical units and whose implementation may differ from what is shown. Figure 1 The connections shown in are logical connections; the actual physical connections may be different. It will be apparent to those skilled in the art that the system may also include Figure 1 Other functions and structures than those shown in .

[0028] However, the exemplary embodiments are not limited to the systems given as examples, but a person skilled in the art may apply the solution to other communication systems having the necessary properties.

[0029] Figure 1 The example of FIG. 1 shows a portion of an exemplary radio access network.

[0030] Figure 1 User equipment 100 and 102 are shown configured to communicate with an access node (AN) 104, such as an evolved Node B (abbreviated as eNB or eNodeB) or a next generation Node B (abbreviated as gNB or gNodeB), in a wireless connection over one or more communication channels, providing a radio cell of the radio cell. The physical link from the user equipment to the access node can be called an uplink (UL) or reverse link, and the physical link from the access node to the user equipment can be called a downlink (DL) or forward link. The user equipment can also communicate directly with another user equipment via sidelink (SL) communications. It should be understood that an access node or its functionality can be implemented using any entity such as a node, host, server, or access point suitable for such usage.

[0031] A communication system may include more than one access node, in which case the access nodes may also be configured to communicate with each other via wired or wireless links designed for this purpose. These links may be used for signaling purposes or for routing data from one access node to another. An access node may be a computing device configured to control the radio resources of the communication system to which it is coupled. An access node may also be referred to as a base station, a base transceiver station (BTS), an access point, or any other type of interface device, including a relay station capable of operating in a wireless environment. An access node may include a transceiver or be coupled to a transceiver. From the transceiver of the access node, a connection may be provided to an antenna unit that establishes a two-way radio link to a user equipment. The antenna unit may include multiple antennas or antenna elements. The access node may also be connected to a core network 110 (CN or next generation core NGC). Depending on the deployed technology, the counterparts to which the access node can be connected on the CN side may be a serving gateway (S-GW, routing and forwarding user data packets), a packet data network gateway (P-GW) for providing user equipment with connectivity to external packet data networks, a user plane function (UPF), a mobility management entity (MME) or an access and mobility management function (AMF), etc.

[0032] Regarding positioning, the service-based architecture (core network) may include the AMF 111 and the Location Management Function (LMF) 112. The AMF can provide location information for call processing, policy, and charging to other network functions in the core network and other entities requesting terminal device positioning. The AMF can receive and manage location requests from multiple sources: mobile-originated location requests (MO-LR) from user equipment and mobile-terminated location requests (MT-LR) from other functions in the core network or other network elements. The AMF selects the LMF for a given request and uses its positioning services to trigger a positioning session. The LMF can then perform positioning upon receiving such a request from the AMF. The LMF can manage the resources and timing of positioning activities. The LMF can request user equipment positioning from one or more access nodes using the Namf_Communication service over the NL1 interface, or the LMF can communicate with the user equipment over N1 for UE-based or UE-assisted positioning. Positioning can include an estimate of location, and upon request, the AMF can also estimate the movement and accuracy of the location information. Connectivity-wise, the AMF can be between the access node and the LMF and therefore closer to the access node than the LMF.

[0033] A positioning session may be associated with signaling for activating devices and / or signals, transferring assistance data, reporting measurement information, and estimating the position of the UE.A positioning session may start with a positioning request.

[0034] User equipment illustrates one type of device that can allocate and assign resources on the air interface, and thus any features of user equipment described herein may be implemented using corresponding devices (eg, relay nodes).

[0035] An example of such a relay node may be a layer 3 relay towards an access node (self-backhaul relay). A self-backhaul relay node may also be referred to as an integrated access and backhaul (IAB) node. An IAB node may include two logical parts: a mobile terminal (MT) part responsible for the backhaul link (i.e., the link between the IAB node and the donor node, also referred to as the parent node) and a distributed unit (DU) part responsible for the access link (i.e., the sub-link between the IAB node and the user equipment, and / or the sub-link between the IAB node and other IAB nodes (multi-hop scenario)).

[0036] Another example of such a relay node may be a layer 1 relay, also known as a repeater, which may amplify signals received from an access node and forward them to a user device, and / or amplify signals received from a user device and forward them to an access node.

[0037] User equipment may also be referred to as a subscriber unit, mobile station, remote terminal, access terminal, user terminal, terminal device, or user equipment (UE), to name a few names or devices. User equipment may refer to a portable computing device, including wireless mobile communication devices 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 or measurement devices), laptop computers and / or touch screen computers, tablet computers, game consoles, notebooks, multimedia devices, reduced capability (RedCap) devices, wireless sensor devices, or any device integrated into a vehicle.

[0038] The user device may also be a device capable of operating in an Internet of Things (IoT) network, which is a scenario in which objects can be provided with the ability to transmit data over a network without requiring human-to-human or human-to-computer interaction. The user device may also utilize the cloud. In some applications, the user device may include a small portable or wearable device with a radio component (such as a watch, headphones, or glasses), and the computation may be performed in the cloud or in another user device.

[0039] The various techniques described here can also be applied to cyber-physical systems (CPS)—systems of collaborative computing elements that control physical entities. CPS can implement and utilize a large number of interconnected ICT devices (sensors, actuators, processors, microcontrollers, etc.) embedded in physical objects at different locations. Mobile cyber-physical systems, where the physical systems in question may have inherent mobility, are a subclass of cyber-physical systems. Examples of mobile physical systems include mobile robots and electronic devices transported by humans or animals.

[0040] Additionally, although the device has been depicted as a single entity, different units, processors and / or memory units may be implemented (not all of which are shown). Figure 1 ).

[0041] 5G supports the use of Multiple Input Multiple Output (MIMO) antennas, many more base stations or nodes than LTE (the so-called small cell concept), including macro sites operating in partnership with smaller sites, and employing a variety of radio technologies depending on service requirements, use cases and / or available spectrum. 5G mobile communications can support a wide range of use cases and related applications, including video streaming, augmented reality, different data sharing methods, and various forms of machine-type applications (such as (massive) machine-type communications (mMTC), including vehicle safety, different sensors, and real-time control. 5G can have multiple radio interfaces, namely sub-6 GHz, cmWave, and mmWave, and can also be integrated with existing traditional radio access technologies (such as LTE). At least in the early stages, integration with LTE can be implemented as a system, where macro coverage can be provided by LTE, and 5G radio interface access can be obtained from small cells by aggregation to LTE. In other words, 5G can support inter-RAT operability (such as LTE-5G) and inter-RI operability (inter-radio interface operability, such as sub-6 GHz-cmWave-mmWave). One of the concepts being considered for 5G networks may be network slicing, in which multiple independent and dedicated virtual subnetworks (network instances) can be created within essentially the same infrastructure to run services with different requirements for latency, reliability, throughput, and mobility.

[0042] Current LTE network architectures may be fully distributed in the radio and fully centralized in the core network. Low-latency applications and services in 5G may require content to be placed close to the radio, leading to local bursting and multi-access edge computing (MEC). 5G may enable analytics and knowledge generation to occur at the source of data. This approach may require leveraging resources that may not be continuously connected to the network, such as laptops, smartphones, tablets, and sensors. MEC may provide a distributed computing environment for hosting applications and services. It may also include the ability to store and process content close to cellular users for faster response times. Edge computing may encompass a wide range of technologies, such as wireless sensor networks, mobile data collection, mobile signature analysis, collaborative distributed peer-to-peer ad hoc networking and processing, and may also be categorized as local cloud / fog computing and grid / grid 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, the Internet of Things (massive connectivity and / or latency-critical), and critical communications (autonomous vehicles, traffic safety, real-time analytics, time-critical control, and healthcare applications).

[0043] The communication system may also be capable of communicating with one or more other networks 113, such as the public switched telephone network or the Internet, or utilizing services provided by them. The communication network may also be capable of supporting the use of cloud services, for example, at least part of the core network operations may be performed as a cloud service (this is in the Figure 1 (depicted by “cloud” 114 in FIG. 1 ). The communication system may also include a central control entity or the like that provides facilities for the networks of different operators to cooperate, for example, in spectrum sharing.

[0044] By leveraging Network Function Virtualization (NFV) and Software Defined Networking (SDN), edge cloud can be introduced into the Radio Access Network (RAN). Using edge cloud can mean performing access node operations at least partially in a server, host, or node that is operatively coupled to a Remote Radio Head (RRH) or Radio Unit (RU), or performing access node operations in an access node that includes the radio part. Node operations can also be distributed among multiple servers, nodes, or hosts. The application of cloud RAN architecture enables RAN real-time functions to be performed on the RAN side (in distributed units, DU 105), while non-real-time functions can be performed in a centralized manner (in centralized units, CU 108).

[0045] It should also be understood that the functional division between core network operations and access node operations may differ from LTE or even not exist. Some other technological advancements that may be used include big data and all-IP, which may change the way networks are built and managed. 5G (or new radio, NR) networks can be designed to support multiple hierarchical structures, where MEC servers can be placed between the core and access nodes. It should be understood that MEC can also be applied to 4G networks.

[0046] 5G can also leverage non-terrestrial communications, such as satellite communications, to enhance or supplement the coverage of 5G services, for example by providing backhaul transport. Possible use cases could be providing service continuity for machine-to-machine (M2M) or Internet of Things (IoT) devices or passengers on a vehicle, or ensuring service availability for critical communications, future geostationary / ocean / aerospace communications. Satellite communications can leverage geostationary (GEO) satellite systems or low earth orbit (LEO) satellite systems, particularly mega-constellations (systems with hundreds of (nano) satellites deployed). A given satellite 106 in a mega-constellation can cover several satellite-enabled network entities that create ground cells. Ground cells can be created by ground relay nodes or by access nodes 104 located on the ground or in a satellite.

[0047] 6G networks are expected to utilize flexible decentralized and / or distributed computing systems and architectures, as well as ubiquitous computing. Based on mobile edge computing, artificial intelligence, short packet communications, and blockchain technologies, they will enable local spectrum licensing, spectrum sharing, infrastructure sharing, and intelligent automated management. Key features of 6G are likely to include intelligent connectivity management and control capabilities, programmability, integrated sensing and communications, a reduced energy footprint, trustworthy infrastructure, scalability, and affordability. Furthermore, 6G targets new use cases, including integrating localization and sensing capabilities into system definitions to unify the user experience across the physical and digital worlds.

[0048] It is obvious to a person skilled in the art that the depicted system is only an example of a part of a radio authority system, and in practice, the system may include multiple access nodes, the user equipment may have access to multiple radio cells, and the system may also include other devices, such as physical layer relay nodes or other network elements, etc., at least one of the access nodes may be a Home eNodeB or a Home gNodeB.

[0049] In addition, the access node can also be divided into: a radio unit (RU), including a radio transceiver (TRX), i.e. a transmitter (Tx) and a receiver (Rx); one or more distributed units (DU), which can be used for so-called layer 1 (L1) processing and real-time layer 2 (L2) processing; and a central unit (CU) (also called a centralized unit), which can be used for non-real-time layer 3 (L2) processing. The CU can be connected to one or more DUs, for example, by using an F1 interface. This division can achieve the centralization of the CU relative to the cell site and the DU, while the DU can be more distributed or even remain at the cell site. The CU and DU together can also be called a baseband or baseband unit (BBU). The CU and DU can also be included in a radio access point (RAP).

[0050] The CU may be defined as a logical node that carries the higher layer protocols of the access node, such as radio resource control (RRC), service data adaptation protocol (SDAP) and / or packet data convergence protocol (PDCP). The DU may be defined as a logical node that carries the radio link control (RLC), medium access rights adaptation (MAC) and / or physical (PHY) layers of the access node. The operation of the DU may be at least partially controlled by the CU. The CU may include a control plane (CU-CP), which may be defined as a logical node that carries the RRC and the control plane portion of the PDCP protocol used by the CU for the access node. The CU may also include a user plane (CU-UP), which may be defined as a logical node that carries the PDCP protocol and the user plane portion of the SDAP protocol used by the CU for the access node.

[0051] The cloud computing platform can also be used to run the CU and / or DU. The CU can run in the cloud computing platform, which can be called a virtualized CU (vCU). In addition to the vCU, there can also be a virtualized DU (vDU) running in the cloud computing platform. In addition, there can also be a combination in which the DU can use a so-called bare metal solution, such as an application-specific integrated circuit (ASIC) or a customer-specific standard product (CSSP) system-on-chip (SoC) solution. It should also be understood that the functional distribution between the above-mentioned access node units, or between different core network operations and access node operations may be different.

[0052] Furthermore, in a geographical area of a radio communication system, a plurality of different kinds of radio cells as well as a plurality of radio cells may be provided. A radio cell may be a macro cell (or umbrella cell), which may be a large cell with a diameter of up to tens of kilometres, or a smaller cell such as a micro cell, a femto cell or a pico cell. Figure 1 An access node can provide any of these cells. A cellular radio system can be implemented as a multi-layer network comprising several types of radio cells. In a multi-layer network, one access node can provide one or more types of radio cells, so multiple access nodes may be required to provide such a network structure.

[0053] In order to meet the need to improve the deployment and performance of communication systems, the concept of "plug and play" access nodes can be introduced. Networks that may be able to use "plug and play" access nodes may include, in addition to Home eNodeBs or Home gNodeBs, Home NodeB Gateways or HNB-GWs ( Figure 1 (not shown). The HNB-GW, which may be installed in an operator's network, may aggregate traffic from a large number of Home eNodeBs or Home gNodeBs back to the core network.

[0054] Positioning techniques can be used to estimate the physical or geographic location of a user equipment (UE). The UE to be positioned is referred to herein as the target UE or target UE. For example, the following positioning techniques can be used for NR: downlink time difference of arrival (DL-TDoA), uplink time difference of arrival (UL-TDoA), downlink angle of departure (DL-AoD), uplink angle of arrival (UL-AoA), and / or multi-cell round trip time (multi-RTT).

[0055] In wireless positioning, multiple positioning anchors at known locations can send and / or receive one or more positioning reference signals (PRS) to the target UE. In the uplink, a sounding reference signal (SRS) can be used as a positioning reference signal. For example, a multi-time point technique can then be used to locate (i.e., position) the target UE relative to the positioning anchor. A positioning anchor may also be referred to herein as an anchor, anchor node, multi-time point anchor, or reference point. A positioning anchor can be, for example, a radio access node (e.g., a gNB) or a transmit and receive point (TRP) (in uplink / downlink positioning), or another UE (in sidelink positioning).

[0056] Sidelink (SL) positioning refers to a positioning method in which the target UE utilizes a sidelink (i.e. a direct device-to-device link) to locate itself in an absolute manner (in the case of absolute positioning, the coordinates of the target UE are obtained in the form of global or local Cartesian coordinates) or in a relative manner (in the case of relative positioning, the position of the target UE is estimated relative to another entity, such as another non-static or anchor UE). For UE-assisted positioning, the target UE can utilize the sidelink to obtain positioning measurements and report the measurements to a network entity, such as a Location Management Function (LMF). Sidelink positioning can also be used to obtain ranging information. Ranging means determining the distance and / or direction between the target UE and another entity, such as an anchor UE.

[0057] Sidelink positioning involves the use of a supporting UE or a group of supporting UEs, referred to as "anchor UEs," which assist in the positioning session of a target UE. Anchor UE support can be achieved in a variety of ways, including the anchor UE estimating the position of the target UE, the target UE obtaining positioning assistance data from the anchor UE, and the target UE measuring reference signals from the anchor UE (or vice versa) for positioning purposes.

[0058] In addition, the Positioning Reference Unit (PRU) can perform positioning measurements such as Reference Signal Time Difference (RSTD), Reference Signal Received Power (RSRP), UE receive-transmit time difference measurements, and report these measurements to a location server, such as the LMF. Furthermore, the PRU can transmit UL SRS for positioning, enabling the Transmit and Receive Point (TRP) to measure and report UL positioning measurements (e.g., relative time of arrival, UL-AoA, gNB receive-transmit time difference, etc.) from a PRU with a known location. From the perspective of the location server, the PRU functionality can be implemented by a UE with a known location.

[0059] The difference between a PRU and an anchor UE is that an anchor UE may not know its own location, while a PRU may know its own location. PRUs may also act as positioning anchors for target UEs, or they may simply provide correction data (e.g., to the LMF) to help locate the target UE.

[0060] In other words, PRUs at known locations can act as reference target UEs, allowing their calculated positions to be compared with their known positions. Under the assumption that the same or similar accuracy determination effect applies to the positions of the PRUs and other target UEs, the comparison of the known and estimated positions can generate correction data that can be used to fine-tune the position estimate of the target UE, thereby improving positioning accuracy.

[0061] The location of the UE can be calculated in the network, for example in the LMF (LMF-based positioning), or in the UE itself (UE-based positioning).

[0062] Measurements used for positioning may be performed at the UE side (eg, in the case of DL positioning) or at the network side (eg, in the case of UL positioning).

[0063] Figure 2An embodiment is shown in which one or more PRUs 202, 202A, 202B are used to locate a target UE 200. The PRUs may be configured to transmit reference signals measured for positioning the target UE 200. The target UE 200 may further transmit reference signals used to locate the target UE 200. One or more access nodes 204, 204A, 204B may measure reference signals received from the PRUs 202, 202A, 202B and from the target UE 200. In the case of sidelink positioning, the target UE 200 may measure reference signals received from the PRUs 202, 202A, 202B, and / or the PRUs 202, 202A, 202B may measure reference signals received from the target UE and / or from other UEs or PRUs. Measurement parameters (measurement data) derived from the received reference signals may include reference signal reception time, reference signal time difference (RSTD), reference signal arrival angle, and / or RSRP, among others. The measurement data may be reported to a network element, a location management function (LMF) 212, which is configured to perform positioning based on the measurement data. The LMF 212 may estimate the position of the target UE 200 based on the received measurement data and the known positions of the PRUs measured by the reporting access node. For example, a position estimation function used in a global navigation satellite system real-time kinematic positioning (RTK) application may be employed. For example, if measurements indicate that the signals received from the target UE 200 and one of the PRUs 202 have a high correlation, the position of the target UE 200 may be estimated to be close to that PRU 202 and away from the other PRUs 202A, 202B. A correction from the position of a given PRU 202A, 202B may be calculated based on the measurement data, for example, by using the difference between the measurement data associated with the target UE 200 and the measurement data associated with the closest PRU 202. For example, multiple measurements (of RSRP, RSTD, and / or other parameters) may indicate that the target UE 200 is in a certain direction from the nearest PRU 202, and a correction may be made in that direction.

[0064] There may be various procedures for activating a PRU. Therefore, for a given positioning service request, it is a challenge to follow which procedure to activate the PRU. For example, similar to the target UE, the PRU may also follow the LTE Positioning Protocol (LPP) procedure. This means that whenever a PRU is to be activated, the LMF may initiate a Location Services (LCS) request for that PRU. However, associating the appropriate PRU (or a group of PRUs) with the target UE is not a simple process, because the network may not know in advance which PRUs can indeed be used as reference devices for applying positioning corrections to the target UE. This is related to the problem that will be described below.

[0065] Finding the right PRU to accurately locate a given target UE using its correction data is challenging in order to determine and activate the appropriate PRU for the positioning session in a short time (latency constraint) and with minimal overhead, i.e. in the sense of low geometric dilution of precision (GDOP). For example, in low latency positioning applications, the (accurate) position of the UE needs to be estimated in a short time. Some examples of such low latency applications may include automotive use cases, where the UE itself can initiate the positioning procedure, for example, via a mobile originated positioning request (MO-LR). In other words, MO-LR means that the request to locate the target UE comes from the target UE itself.

[0066] For example, the positioning latency requirement may be set to only a few milliseconds. Low latency becomes even more challenging if the additional time required to select and configure the appropriate PRU (i.e., the PRU used to provide assistance data for fine-tuning the target UE position) is calculated.

[0067] Another challenging aspect is that, in contrast to Global Navigation Satellite System (GNSS) positioning, in terrestrial positioning, techniques for improving positioning accuracy based on correction data may require that the PRU and the target UE experience the same (or substantially the same) radio conditions. That is, in order to be able to apply the same correction data as the PRU to the target UE, the target UE and the PRU may need to be measured by the same set of TRPs and have the same conditions (e.g., line of sight, bandwidth, measurement capabilities, etc.). This means that the PRU and the target UE should have similar measurement capabilities and be as close to each other as physically possible.

[0068] The legacy LPP-based method for activating PRUs may require the LMF to initiate an LCS request to the PRU after receiving an LCS request for the target UE. Furthermore, the LMF may need to make a very accurate estimate of the target UE's location to identify the correct PRU. This results in high latency because, in principle, this means the LMF may need to run two positioning procedures one after the other: one to estimate the target UE's location; followed by another to activate the PRU and estimate its location based on a stored database. Finally, based on the estimated PRU location, the LMF can refine the target UE's location estimate.

[0069] Given that the activated PRUs have their available measurements, some exemplary embodiments may enable selection of measurements at one or more PRUs and / or LMF side to be associated with the target UE measurements to improve the accuracy of the target UE's position estimate.

[0070] Some example embodiments may be used for UL positioning, as UL positioning may be suitable for correcting the target UE position using correction data from the PRU. In DL positioning, there is an additional requirement that the PRU and the target UE should have the same (or very similar) measurement capabilities, which is not the case for UL positioning, where the measurements (by the target UE and the PRU) are performed by the same gNB or TRP.

[0071] However, some exemplary embodiments are not limited to UL positioning, and they can also be used for sidelink positioning, for example.

[0072] In order to process the reported measurements of the activated PRUs at the LMF, select a PRU from a given list and associate it with a set of positioning measurements to improve the position estimate of the target UE, some exemplary embodiments may be based on the following principles:

[0073] 1) If the SRS of the PRU is measured by the same gNB / TRP as the target UE SRS

[0074] If the PRU is measured, the PRU should be associated with the target UE. In other words, the PRU positioning session and the target UE positioning session should involve the same set of gNBs / TRPs. This is to ensure that the PRU is close enough to the target UE.

[0075] 2) In addition, the flight time of the SRS sent from the PRU should be similar (i.e. within certain thresholds / limits) to the flight time of the target UE SRS. This is to ensure that the PRU and the target UE experience similar line-of-sight (LOS) conditions, so that if the target UE sees a set of gNBs with LOS, then the PRU will also see the same set of gNBs with LOS.

[0076] Some example embodiments will be described below using the principles and terminology of 5G technology, but this does not limit the example embodiments to 5G communication systems.

[0077] Figure 3 A flow chart of a method according to an example embodiment is shown, the method being performed by a network element such as a core network, or a device included in a network element of the core network. For example, the network element may be a location management function (LMF). The network element may correspond to the LMF 112 and / or Figure 2 LMF 212.

[0078] Reference Figure 3 In block 301, a first set of measurement information is obtained, where the first set of measurement information is associated with a reference signal transmitted from a positioning reference element set. For example, the first set of measurement information may be received from one or more network nodes (e.g., a gNB or a TRP) that measure received reference signals.

[0079] For example, the first measurement information set may include at least one of the following measurements of reference signals sent from the positioning reference unit set of a given PRU: reference signal received power (RSRP), reference signal received quality (RSRQ), received signal strength indicator (RSSI), signal-to-noise ratio (SNR), signal-to-interference and noise ratio (SINR), arrival time, receive-transmit (Rx-Tx) time difference, relative time of arrival (RTOA), arrival angle (azimuth and elevation), beam information, a timestamp of the measurement, and / or the quality of a given measurement.

[0080] The reference signal sent from the positioning reference element set may be any signal, such as an uplink sounding reference signal (UL SRS) or a sidelink positioning reference signal (SL PRS).

[0081] In block 302, a subset of positioning reference elements is selected from a set of positioning reference elements, wherein the selection is based at least on determining that a reference signal transmitted by each positioning reference element of the subset of positioning reference elements is measured by the same set of network nodes that measure a reference signal transmitted from a target user equipment. The subset of positioning reference elements is further selected based on at least one of: a comparison of a time of flight of the reference signal transmitted by each positioning reference element of the subset of positioning reference elements with a time of flight of a reference signal transmitted from the target user equipment, or a comparison of a timing advance of each positioning reference element of the subset of positioning reference elements with a timing advance of the target user equipment.

[0082] The reference signal transmitted from the target user equipment may be any signal, such as an uplink sounding reference signal (UL SRS) or a sidelink positioning reference signal (SL PRS).

[0083] A network node set may include one or more network nodes, such as (multiple) gNBs or (multiple) TRPs.

[0084] In block 303, a position estimate of a target user equipment is refined based on at least a subset of measurement information from the first measurement information set, wherein the subset of measurement information is associated with a subset of positioning reference units.

[0085] Refinement of the position estimate may mean using a subset of measurement information to provide correction data for fine-tuning a previously acquired position estimate of a target user equipment, thereby improving its accuracy. The subset of measurement information may be used to calculate the position of a subset of PRUs, which may then be compared with the known positions (true positions) of these PRUs to obtain correction data that can be applied to the position estimate of the target user equipment. This correction data may be used to correct the position estimate of the target user equipment, which may have similar channel conditions as the PRU subset under consideration.

[0086] The target user equipment may also be referred to herein as a target UE.

[0087] Figure 4 A flow chart of a method according to an example embodiment is shown, the method being performed by a network element such as a core network, or a device included in a network element of the core network. For example, the network element may be a location management function (LMF). The network element may correspond to the LMF 112 and / or Figure 2 LMF 212.

[0088] Figure 4 Shows how to target Figure 3 An example of selecting a subset of positioning reference units in block 302 of FIG. 1 is provided. In this example embodiment, the LMF may down-select among the activated PRUs to optimize the selection of PRUs for measurement to improve the position estimate of the target user equipment. This example embodiment on the network (e.g., LMF) side is based on comparing the set of network nodes that are measuring a reference signal (e.g., UL SRS) from the target user equipment and the PRU, such that if the reference signal of the PRU is measured by the same set of network nodes as the reference signal of the target user equipment, the PRU is considered to be associated with the target user equipment.

[0089] Reference Figure 4 In block 401, a device (e.g., LMF) receives a PRU activation request message and activates an associated positioning reference unit set. Alternatively, the positioning reference unit set may be activated by a target user equipment or by one or more network nodes. The activated PRU and target user equipment may transmit a reference signal such as a UL SRS. One or more network nodes, such as a gNB or TRP, that are capable of measuring an SRS of a given quality, for example by measuring RSRP within a certain range, may report the measurement value to the device. The device collects the measurement report.

[0090] In block 402, one or more first network nodes are marked based on a second set of measurement information reported from one or more first network nodes within one or more restrictions, wherein the second set of measurement information is associated with a reference signal transmitted from a target user equipment. The one or more first network nodes may also be denoted herein as set A. The one or more first network nodes may include, for example, one or more gNBs or TRPs.

[0091] The second measurement information set may refer to a measurement report associated with the target user equipment. For example, the second measurement information set may include at least one of the following measurements of a reference signal sent from the target user equipment: reference signal received power (RSRP), reference signal received quality (RSRQ), received signal strength indicator (RSSI), signal-to-noise ratio (SNR), signal-to-interference noise ratio (SINR), time of arrival, receive-transmit (Rx-Tx) time difference, UL relative time of arrival (RTOA), UL arrival angle (azimuth and elevation), beam information, a timestamp of the measurement, and / or the quality of a given measurement.

[0092] The second measurement information set being within one or more limits may, for example, mean that the reported RSRP values included in the second measurement information set are within a certain range, i.e., above a lower limit and / or below an upper limit. In other words, as an example, a device (e.g., LMF) may flag a gNB or TRP that reports the SRS of the target user equipment with sufficient quality (e.g., receiving an SRS RSRP within a certain range).

[0093] In block 403, the apparatus marks one or more second network nodes as being within the one or more limits based on each positioning reference unit of the positioning reference unit set based on a first set of measurement information reported from the one or more second network nodes. The one or more second network nodes may also be denoted herein as set B. The one or more second network nodes may include, for example, one or more gNBs or TRPs. The one or more second network nodes may be the same as or different from the one or more first network nodes.

[0094] The first measurement information set may refer to a measurement report associated with a given PRU in the set of PRUs. For example, the first measurement information set may include at least one of the following measurements of a reference signal sent from a positioning reference unit: reference signal received power (RSRP), reference signal received quality (RSRQ), received signal strength indicator (RSSI), signal-to-noise ratio (SNR), signal-to-interference noise ratio (SINR), time of arrival, receive-transmit (Rx-Tx) time difference, UL relative time of arrival (RTOA), UL arrival angle (azimuth and elevation), beam information, a timestamp of the measurement, and / or the quality of the given measurement.

[0095] The first measurement information set being within one or more limits may, for example, mean that the RSRP values included in the first measurement information set are within a certain range, i.e., above a lower limit and / or below an upper limit. In other words, as an example, for each candidate PRU, the device may mark the gNB(s) or TRP(s) that report PRU RSRP with sufficient quality (e.g., receive SRS RSRP within a range similar to the SRS RSRP of the target user equipment).

[0096] In block 404, the apparatus may compare the identities of one or more first network nodes and one or more second network nodes based on each positioning reference unit of the set of positioning reference units. In other words, the apparatus may compare the identities of gNBs or TRPs belonging to set A and set B.

[0097] Based on the comparison of the identities, the apparatus may determine whether the reference signal transmitted by each positioning reference unit of the subset of positioning reference units is measured by the same group of network nodes that measured the reference signal transmitted from the target user equipment. In other words, if the identities of the one or more first network nodes and the one or more second network nodes are the same, the apparatus may determine that they comprise the same group of network nodes.

[0098] If the identities of Set A and Set B are not the same (Block 404: No), then this PRU is not associated with the target user equipment and the process returns to Block 403 for processing the next PRU in the PRU set.

[0099] Alternatively, in block 405, if the identities of set A and set B are the same (block 404: yes), then the PRU is associated with the target user equipment and the positioning reference unit subset is selected.

[0100] After block 405, the process may return to block 403 to process the next PRU in the PRU set. In other words, blocks 403-405 may be performed iteratively until all PRUs in the PRU set are processed.

[0101] In block 406, after all PRUs in the PRU set are processed, the device acquires a subset of positioning reference units that includes the PRU associated with the target user equipment.

[0102] Figure 5 A flow chart of a method according to an example embodiment is shown, the method being performed by a network element such as a core network, or a device included in a network element of the core network. For example, the network element may be a location management function (LMF). The network element may correspond to the LMF 112 and / or Figure 2 LMF 212.

[0103] Figure 5 Shown for Figure 3

[0046] Another example of how block 302 may select a subset of positioning reference cells. Figure 5 It shows how to select down to a subset of PRUs associated with each target user equipment. Figure 5 The method can be Figure 4 is executed in addition to or as an alternative to the method of

[0104] In this example embodiment, for example, reference is made to Figure 4 Out of the acquired subset of PRUs, the LMF may perform a down-selection of those PRUs corresponding to the measured reference signals whose flight time is within a certain limit compared to the flight time of the reference signal of the target user equipment.

[0105] In other words, in this example embodiment, the subset of positioning reference units may be further selected based on a comparison of the flight time of the reference signal transmitted by each positioning reference unit with the flight time of the reference signal transmitted from the target user equipment. For each PRU associated with the target user equipment, the device (e.g., LMF) may perform another association process based on the flight time and down-select the PRU associated with the target user equipment, as described below.

[0106] Reference Figure 5 In block 501, obtain the Figure 4 The positioning reference unit subset is obtained, and the subset may be referred to as a first positioning reference unit subset.

[0107] In block 502, arrival times and departure times of positioning reference elements for a first subset of reference signals (eg, UL SRS) transmitted by a target user equipment and each positioning reference element are obtained.

[0108] For example, a device (e.g., LMF) may collect time of arrival (ToA) values reported by one or more network nodes (e.g., gNB or TRP), which measures the time of arrival of a reference signal sent by each PRU and target user equipment.

[0109] A device (e.g., LMF) may obtain the scheduled departure time of the reference signal for each PRU and target user equipment from the serving gNB of the PRU and target user equipment, for example, via NR Positioning Protocol A (NRPPa). The PRU and target user equipment may be served by the same or different gNBs.

[0110] In block 503, a device (e.g., LMF) determines or calculates a time-of-flight value for a target user equipment, wherein the time-of-flight value for the target user equipment indicates a difference between a departure time of a reference signal sent from the target user equipment and an arrival time of the reference signal sent from the target user equipment. In other words, the time-of-flight of the target user equipment may be defined as a difference between a predetermined departure time and a reported arrival time of a reference signal sent from the target user equipment.

[0111] In block 504, an apparatus (e.g., an LMF) determines or calculates a time-of-flight value for each positioning reference unit of the first subset of positioning reference units, wherein the time-of-flight value for each positioning reference unit indicates a difference between a departure time of a reference signal transmitted from the positioning reference unit and an arrival time of the reference signal transmitted from the positioning reference unit. In other words, the time-of-flight for a given PRU may be defined as the difference between a predetermined departure time and a reported arrival time of a reference signal transmitted by the PRU.

[0112] In block 505, a device (eg, LMF) compares the time-of-flight value of the target user equipment with the time-of-flight value of each positioning reference cell.

[0113] If the difference between the time of flight values is not greater than the threshold (block 505: YES), the process may return to block 504 to process the next PRU in the first subset of PRUs. The threshold may be defined, for example, based on positioning requirements.

[0114] Alternatively, in block 506, if the difference between the time-of-flight values is greater than a threshold (block 504: No), the PRU is removed from the PRU list associated with the target user equipment. In other words, the device (e.g., LMF) may remove the one or more positioning reference units from the first subset of positioning reference units based on a comparison of the time-of-flight value of the target user equipment with the time-of-flight value of the one or more positioning reference units being greater than a threshold.

[0115] After block 506, the process may return to block 504 to process the next PRU in the first subset of PRUs. In other words, blocks 504-506 may be iteratively performed until all PRUs in the first positioning reference unit subset are processed.

[0116] In block 507 , the LMF obtains a second subset of PRUs associated with the target user equipment. The second PRU subset may be a subset of the first PRU subset, i.e., as described above, the second PRU subset may be obtained by removing one or more PRUs from the first PRU subset based on flight time.

[0117] The LMF may use the second subset of PRUs to perform refinement (fine tuning) of the location estimate of the target user equipment, such as Figure 3 In other words, Figure 3 The PRU subset mentioned in block 302 of may refer to the second subset of PRUs obtained here. In this case, Figure 3 In block 303 of , the subset of measurement information may be associated with reference signals transmitted from a second subset of positioning reference elements, one or more positioning reference elements being removed from the second subset compared to the first subset of positioning reference elements.

[0118] Figure 6A flow chart of a method according to an example embodiment is shown, the method being performed by a network element such as a core network, or a device included in a network element of the core network. For example, the network element may be a location management function (LMF). The network element may correspond to the LMF 112 and / or Figure 2 LMF 212.

[0119] Figure 6 Shown for Figure 3 Another example of how block 302 of FIGURE 3 may select a subset of positioning reference units is provided below. In this example embodiment, the selection of the subset of positioning reference units may be further based on a comparison of the timing advance of each positioning reference unit in the subset of positioning reference units with the timing advance of the target user equipment. In other words, the device (e.g., LMF) may associate one or more PRUs to the target user equipment based on similarity with the timing advance (TA) of different network nodes (e.g., gNB or TRP). Figure 6 The method is Figure 4-5 may be performed in addition to or as an alternative to any method of

[0120] Reference Figure 6 In block 601, a device (eg, LMF) obtains timing advance values allocated to a target user equipment by a plurality of network nodes.

[0121] In block 602, an apparatus (eg, a LMF) obtains timing advance values assigned to a set of positioning reference cells by a plurality of network nodes.

[0122] In block 603, for each network node of the plurality of network nodes, a device (eg, LMF) compares a timing advance value of a target user equipment with timing advance values of a set of positioning reference units.

[0123] In block 604, for each of the plurality of network nodes, a device (e.g., LMF) marks one or more PRUs whose timing advance values are within a predefined interval compared to a timing advance value of a target user equipment. The interval may be based on a positioning accuracy requirement.

[0124] After block 604, processing may return to block 603 for processing the next network node in the plurality of network nodes. In other words, blocks 603-604 may be iteratively performed until each network node in the plurality of network nodes has been processed. Thus, for each network node, the LMF may mark PRUs having a TA that is within an interval around the TA of the target user equipment.

[0125] In block 605, after processing all of the plurality of network nodes, a device (e.g., LMF) determines which PRUs to associate with the target user equipment based on the number of network nodes for which the PRUs have been marked. For example, the LMF may determine to associate one or more PRUs that are marked for a greater number of network nodes (i.e., more gNBs / TRPs are preferred) than other PRUs.

[0126] In block 606, a device (e.g., a LMF) obtains a subset of positioning reference units that includes PRUs associated with the target user equipment. In other words, the subset of positioning reference units may be selected based on the number of network nodes for which the timing advance values of the subset of positioning reference units are within a predefined interval of the timing advance value of the target user equipment. For example, the LMF may select one or more PRUs that are marked for a higher number of network nodes than other PRUs.

[0127] Figure 7 A flow chart of a method performed by an apparatus such as a user equipment, or included in a user equipment, according to an example embodiment is shown. A user equipment may also be referred to as a subscriber unit, a mobile station, a remote terminal, an access terminal, a user terminal, a terminal device, a user equipment (UE), a target UE, or a target user equipment. The user equipment may correspond to the user equipment 100 of FIG. and / or the target UE 200 of FIG.

[0128] The example embodiments relate to a target user equipment identifying how to trigger activation of a PRU based on the RRC state of the target user equipment and / or based on the number of network nodes and PRUs detected over the Uu and SL interfaces, respectively.

[0129] Reference Figure 7 In block 701, an activation procedure is initiated for activating one or more positioning reference units for a positioning session of a device, wherein the activation procedure is initiated based on at least one of: a radio resource control state of the device, a number of detected network nodes, or a number of detected positioning reference units.

[0130] The radio resource control state of the device may refer to, for example, a radio resource control connected state (RRC_CONNECTED), a radio resource control inactive state (RRC_INACTIVE), or a radio resource control idle state (RRC_IDLE).

[0131] For example, if the device (target user equipment) detects SL reference signals from a PRU of sufficient quality, SL-based activation of the PRU may be triggered. If this is not the case, the device may trigger gNB-based PRU activation if in RRC_CONNECTED state, or trigger UL small data transfer (SDT) to establish timing advance (TA) with the gNB if in RRC_IDLE or RRC_INACTIVE state, if a sufficiently large number of gNBs are detected.

[0132] A network node may be considered detected if a signal metric such as RSRP measured from a signal received from the network node is above a threshold. Similarly, a positioning reference cell may be considered detected if a signal metric such as RSRP measured from a signal received from the positioning reference cell is above a threshold.

[0133] Figure 8 A flow chart of a method performed by an apparatus such as a user equipment, or included in a user equipment, according to an example embodiment is shown. A user equipment may also be referred to as a subscriber unit, a mobile station, a remote terminal, an access terminal, a user terminal, a terminal device, a user equipment (UE), a target UE, or a target user equipment. The user equipment may correspond to the user equipment 100 of FIG. and / or the target UE 200 of FIG.

[0134] Figure 8 shows how the target user equipment can determine the target Figure 7 This example illustrates which activation procedure is initiated in block 701. In this example embodiment, the target user equipment may determine to initiate one or more procedures for PRU activation / usage. For example, the target user equipment may request its serving gNB to activate its serving PRUs. As another example, PRU activation may be performed via small data transfer (SDT) by establishing timing advance with the resident and neighboring gNBs.

[0135] When a positioning request arrives at (or originates from) the target user equipment, it can determine which activation procedure to trigger to utilize PRUs to improve its positioning accuracy (unless one or more of them are explicitly requested by the network), as will be described below.

[0136] Reference Figure 8 , in block 801 , the target user equipment checks which RRC state the target user equipment is in, ie, whether the target user equipment is in RRC_CONNECTED, RRC_INACTIVE or RRC_IDLE state.

[0137] In block 802, if the target user equipment is in the RRC_CONNECTED state (block 801: YES), an activation procedure is initiated by sending a request to the network node to activate one or more positioning reference units, which may also be referred to herein as gNB-based PRU activation. In other words, in this case, the activation procedure may be initiated based on the device being in the radio resource control connected state.

[0138] Alternatively, in box 803, if the target user equipment is not in the RRC connected state (box 801: No), that is, the target user equipment is in the RRC_INACTIVE or RRC_IDLE state, the target user equipment can check whether it can detect a signal from a network node and determine the number of detected network nodes, which can be, for example, a gNB or a TRP.

[0139] If a DL measurement value of a signal received from the network node is above a threshold, the network node may be considered to have detected RSRP or another DL measurement value, wherein the threshold may be (pre-)configured by the network device to the target user.

[0140] In block 804, the target user equipment may determine a first threshold for the number of network nodes. When the target user equipment is in an RRC_CONNECTED state, the first threshold may be calculated at the target user equipment based on assistance data provided by the network. The assistance data may include information about a PRS configuration, which may be used by the target user equipment to determine a minimum number of network nodes (the first threshold) that should be detected to achieve a given positioning accuracy. For example, the assistance data may include information about at least one of the following: a PRS bandwidth, a PRS periodicity and duration, and / or a positioning time instance.

[0141] Alternatively, the first threshold for the number of network nodes may be calculated and / or preconfigured on the network side and provided from the network to the target user equipment (e.g., from its serving gNB).

[0142] In block 805, if the target user equipment is not in the RRC connected state (block 801: No), the target user equipment may determine the number of PRUs detected on the SL. A PRU may be considered detected if the SL RSRP or another SL measurement measured from the signal received from the PRU is above a threshold.

[0143] In block 806, the target user equipment may determine a second threshold for the number of PRUs. When the target user equipment is in an RRC connected state, the second threshold may be calculated at the target user equipment based on assistance data provided by the network. In this case, the assistance data may include information about the SL PRS configuration, which may be used by the target user equipment to determine the minimum number of positioning reference units (the second threshold) that should be detected to achieve a certain positioning accuracy. For example, the assistance data may include information about at least one of the following: the bandwidth of the SL PRS, the periodicity and duration of the SL PRS, and / or the positioning time occasion.

[0144] Alternatively, a second threshold for the number of PRUs may be calculated and / or preconfigured on the network side and provided to the target user equipment from the network (e.g., from its serving gNB). The second threshold may be the same as or different from the first threshold.

[0145] Blocks 805 - 806 may be performed in addition to or instead of blocks 803 - 804 .

[0146] In block 807 , the target user equipment checks whether the number of detected network nodes is higher than a first threshold, and / or whether the number of detected positioning reference units is higher than a second threshold.

[0147] In block 808, if the number of detected network nodes is higher than a first threshold, and / or the number of detected positioning reference units is higher than a second threshold (block 807: yes), an activation procedure is initiated via a small data transmission (SDT) to establish a timing advance with the network node. That is, if at least a certain number of network nodes and / or PRUs are detected, the target user equipment may initiate an activation procedure via UL SDT to establish a timing advance with the network node.

[0148] In other words, the activation process may be initiated via a small data transmission based on at least one of the following: the number of detected network nodes is greater than a first threshold, or the number of detected positioning reference units is greater than a second threshold. Furthermore, the activation process may be initiated via a small data transmission based on the device being in a radio resource control idle or inactive state.

[0149] If the number of detected network nodes is not higher than a first threshold and the number of detected positioning reference units is not higher than a second threshold, the activation process may not be initiated.

[0150] SDT is a procedure that allows data transmission while remaining in the RRC_INACTIVE or RRC_IDLE state (i.e., without transitioning to the RRC_CONNECTED state). Therefore, the SDT procedure can avoid the signaling overhead and delay associated with transitioning from the RRC_INACTIVE or RRC_IDLE state to the RRC_CONNECTED state. If the amount of uplink data to be transmitted is less than the data amount threshold, a UE in the inactive or idle state can initiate a small data transmission procedure.

[0151] Figure 9 A flow chart of a method performed by an apparatus such as a user equipment, or included in a user equipment, according to an example embodiment is shown. A user equipment may also be referred to as a subscriber unit, a mobile station, a remote terminal, an access terminal, a user terminal, a terminal device, a user equipment (UE), a target UE, or a target user equipment. The user equipment may correspond to the user equipment 100 of FIG. and / or the target UE 200 of FIG.

[0152] In this example embodiment, the target user equipment may check whether it can detect SL signals from other UEs (e.g., PRUs) in its vicinity. If a SL UE (PRU) is detected, the target user equipment may trigger activation of the SL-based PRU by broadcasting an activation request via the sidelink to activate one or more PRUs in its vicinity. Figure 9 The method can be used as Figure 8 to be performed in addition to or as an alternative to the method of

[0153] Reference Figure 9 In block 901, one or more positioning reference cells are detected. For example, if a signal metric such as RSRP measured from a signal received from the one or more positioning reference cells via a sidelink is above a threshold, the one or more positioning reference cells may be detected.

[0154] In block 902, an activation procedure is initiated to activate one or more positioning reference units for use in a positioning session for a device, wherein the activation procedure is initiated by sending an activation request to the one or more positioning reference units via a sidelink. In this case, the activation procedure may be initiated based on the number of detected positioning reference units, i.e., based on the detection of one or more positioning reference units. In other words, the number of detected positioning reference units may include at least one or more positioning reference units.

[0155] exist Figure 9 In an example embodiment of the present invention, the device may be in any RRC state, such as RRC_CONNECTED state, RRC_INACTIVE state, or RRC_IDLE state.

[0156] Figure 10 A signaling diagram according to an example embodiment is illustrated.

[0157] See also Figure 10 In block 1001, the target user equipment initiates an activation procedure for activating one or more positioning reference elements for use in a positioning session of the target user equipment, wherein the activation procedure is initiated based on at least one of the following: a radio resource control state of the target user equipment, a number of detected network nodes, and / or a number of detected positioning reference elements. For example, the activation procedure may be as described above with reference to Figure 7-9 Initiated as described in any of the .

[0158] In block 1002, a target user equipment sends a reference signal, such as a UL SRS, to one or more first network nodes (e.g., a gNB or a TRP).

[0159] In block 1003, once activated, one or more positioning reference units transmit a reference signal, such as a UL SRS, to one or more second network nodes (e.g., a gNB or a TRP), at least some of which may be the same as the one or more first network nodes.

[0160] In block 1004, one or more first network nodes measure a reference signal sent from a target user equipment, and one or more second network nodes measure a reference signal sent from one or more positioning reference elements.

[0161] In block 1005, one or more second network nodes report to a location management function a first set of measurement information associated with reference signals sent from a set of positioning reference elements, wherein the set of positioning reference elements includes at least one or more positioning reference elements activated for a positioning session of a target user equipment.

[0162] Furthermore, the one or more first network nodes report a second set of measurement information associated with the reference signal sent from the target user equipment to the location management function.

[0163] In block 1006, the location management function selects a subset of positioning reference units from the set of positioning reference units, wherein the selection is based at least on determining that a reference signal transmitted by each positioning reference unit of the subset of positioning reference units is measured (or measured) by the same set of network nodes that measure the reference signal transmitted from the target user equipment. For example, the subset of positioning reference units may be as described above with reference to Figure 3-6 Any one of the described ones is selected.

[0164] In block 1007, the location management function refines the location estimate of the target user equipment based on at least a subset of measurement information from the first measurement information set, wherein the subset of measurement information is associated with the selected subset of positioning reference units.

[0165] The above-mentioned Figure 3-10 The blocks, related functions, and information exchanges (messages) described are not in absolute chronological order; some of them may be executed simultaneously or in a different order than described. Other functions may be executed between or within them, and other information may be sent and / or other rules may apply. Some blocks, portions of blocks, or one or more pieces of information may also be omitted or replaced with corresponding blocks, portions of blocks, or one or more pieces of information.

[0166] As used herein, “at least one of: ” and “at least one of ” and similar expressions, where a list of two or more elements is joined by “and” or “or”, mean at least any one element, or at least any two or more elements, or at least all elements.

[0167] Figure 11 An example scenario is shown for the gNB, PRU, and target UE scenarios. In a multi-PRU scenario, the LMF can also select multiple PRUs for correction measurements, where a given PRU may be associated with different positioning measurements belonging to different anchor nodes (e.g., gNBs). In general, for a given TRP, a different PRU may be selected if it is in better differential measurement condition compared to other PRU candidates.

[0168] For example, in Figure 11 In Figure 1101, the target UE and PRU1 are approximately the same distance relative to gNB1, as visualized by disk 1101. However, from the perspective of gNB2, PRU1 is not approximately the same distance from the target UE. As visualized by disk 1102, PRU2 is more appropriately associated with correcting measurements involving gNB2. On the other hand, PRU3 is not co-located with the target UE at all, and the TA from gNB1 and gNB2 will be substantially different from the TA of the target UE and PRU3.

[0169] LMF can improve the quality of differential PRU measurements by correlating measurements from PRU1 with measurements obtained using the TRP of gNB1, and correlating PRU2 with measurements obtained using the TRP of gNB2.

[0170] It should be noted that similarity of timing advances from a single gNB may not by itself be a satisfactory condition for PRU selection. The PRU should also be located in the vicinity of the target UE itself, e.g. Figure 11This is visualized in the figure by a circle 1103 indicating the maximum allowed range of the target user equipment to avoid the situation where the target user equipment and the PRU share a similar TA (i.e., they are both located on disk 1101 or disk 1102 of the figure) but are not located at the same position (e.g., they are located on opposite halves of the disk).

[0171] Figure 12 An example of an apparatus 1200 is shown, which includes a method for performing Figure 7-9 Any method or apparatus of any other example embodiment described above. For example, apparatus 1200 may be an apparatus such as, or including, or contained in a user equipment. Apparatus 1200 may correspond to Figure 1 The user equipment 100 and / or target UE 200 of FIG. Apparatus 1200 may also be referred to as a subscriber unit, mobile station, remote terminal, access terminal, user terminal, terminal device, user equipment (UE), target UE, or target user equipment.

[0172] The apparatus 1200 includes at least one processor 1210. The at least one processor 1210 interprets computer program instructions and processes data. The at least one processor 1210 may include one or more programmable processors. The at least one processor 1210 may include programmable hardware with embedded firmware, and may alternatively or additionally include one or more application-specific integrated circuits (ASICs).

[0173] The at least one processor 1210 is coupled to at least one memory 1220. The at least one processor is configured to read data from and write data to the at least one memory 1220. The at least one memory 1220 may include one or more memory cells. The memory cells may be volatile or non-volatile. It should be noted that there may be one or more non-volatile memory cells and one or more volatile memory cells, or, alternatively, one or more non-volatile memory cells. Volatile memory may be, for example, random access memory (RAM), dynamic random access memory (DRAM), or synchronous dynamic random access memory (SDRAM). Non-volatile memory may be, for example, read-only memory (ROM), programmable read-only memory (PROM), electronically erasable programmable read-only memory (EEPROM), flash memory, optical storage, or magnetic storage. In general, memory may be referred to as non-transitory computer-readable media. As used herein, the term "non-transitory" is a limitation of the medium itself (i.e., tangible, not a signal), rather than a limitation on the persistence of data storage (e.g., RAM vs. ROM). At least one memory 1220 stores computer-readable instructions executed by at least one processor 1210 to perform one or more of the above-described example embodiments. For example, non-volatile memory stores computer-readable instructions, and at least one processor 1210 executes instructions using volatile memory for temporary storage of data and / or instructions. Computer-readable instructions may refer to computer program code.

[0174] The computer-readable instructions may have been pre-stored in at least one memory 1220, or alternatively or additionally, they may be received by the device via an electromagnetic carrier signal and / or may be copied from a physical entity such as a computer program product. Execution of the computer-readable instructions by at least one processor 1210 causes the device 1200 to perform one or more of the above-described example embodiments. That is, at least one processor and at least one memory storing instructions may provide a means for providing or causing the performance of any of the methods and / or blocks described above.

[0175] In the context of this document, "memory" or "computer-readable medium" or "computer-readable medium" can be any non-transitory medium or medium or device that can contain, store, communicate, propagate or transport instructions for use by or in connection with an instruction execution system, device or apparatus such as a computer. The term "non-transitory" as used herein is a limitation on the medium itself (i.e., tangible, not a signal), not on the persistence of data storage (e.g., RAM vs. ROM).

[0176] The device 1200 may also include or be connected to an input unit 1230. The input unit 1230 may include one or more interfaces for receiving input. The one or more interfaces may include, for example, one or more temperature, motion, and / or orientation sensors, one or more cameras, one or more accelerometers, one or more microphones, one or more buttons, and / or one or more touch detection units. In addition, the input unit 1230 may include an interface to which external devices may be connected.

[0177] Device 1200 may also include an output unit 1240, which may include or be connected to one or more displays capable of presenting visual content, such as a light emitting diode (LED) display, a liquid crystal display (LCD), and / or a liquid crystal on silicon (LCoS) display. Output unit 1240 may also include one or more audio outputs, which may be, for example, speakers.

[0178] The device 1200 also includes a connection unit 1250. The connection unit 1250 enables wireless connection to one or more external devices. The connection unit 1250 includes at least one transmitter and at least one receiver, which can be integrated into the device 1200 or the device 1200 can be connected to the device 1200. The at least one transmitter includes at least one transmit antenna, and the at least one receiver includes at least one receive antenna. The connection unit 1250 may include an integrated circuit or a set of integrated circuits that provide wireless communication capabilities for the device 1200. Alternatively, the wireless connection may be a hardwired application-specific integrated circuit (ASIC). The connection unit 1250 may include one or more components, such as a power amplifier, a digital front end (DFE), an analog-to-digital converter (ADC), a digital-to-analog converter (DAC), a frequency converter, a (de)modulator, and / or an encoder / decoder circuit, controlled by corresponding control units.

[0179] It should be noted that the device 1200 may also include Figure 12 Various components not shown in the figure may be hardware components and / or software components.

[0180] Figure 13 An example of a device 1300 is shown, which includes a device for performing Figure 3-6 The present invention relates to any method or apparatus of any other example embodiment described above. For example, device 1300 may be a network element such as a core network, or a device included in a network element of a core network. For example, the network element may correspond to LMF 112, 212. The network element may also be referred to as a core network entity or a location server, for example.

[0181] Device 1300 may include, for example, circuitry or a chipset suitable for implementing one or more of the above-described example embodiments. Device 1300 may be an electronic device including one or more electronic circuits. Device 1300 may include communication control circuitry 1310, such as at least one processor, and at least one memory 1320 storing instructions 1322 that, when executed by the at least one processor, cause device 1300 to perform one or more of the above-described example embodiments. These instructions 1322 may include computer program code (software), wherein the at least one memory and the computer program code (software) are configured to cause device 1300 to perform one or more of the above-described example embodiments. The at least one processor and the at least one memory storing instructions may provide means for providing or causing the performance of any of the methods and / or blocks described above.

[0182] Memory cells can be volatile or non-volatile. Note that there can be one or more non-volatile memory cells and one or more volatile memory cells, or, alternatively, one or more non-volatile memory cells, or, alternatively, one or more volatile memory cells, or, alternatively, one or more volatile memory cells. Volatile memory can be, for example, random access memory (RAM), dynamic random access memory (DRAM), or synchronous dynamic random access memory (SDRAM). Non-volatile memory can be, for example, read-only memory (ROM), programmable read-only memory (PROM), electronically erasable programmable read-only memory (EEPROM), flash memory, optical storage, or magnetic storage. In general, memory can be referred to as non-transitory computer-readable media. The term "non-transitory" as used herein refers to the limitation of the medium itself (i.e., tangible, not a signal), not to the persistence of data storage (e.g., RAM vs. ROM). Memory 1320 stores computer-readable instructions executed by the processor. For example, non-volatile memory stores computer-readable instructions, and the processor uses volatile memory to execute instructions for temporary storage of data and / or instructions.

[0183] The computer readable instructions may have been pre-stored in the memory 1320, or, alternatively or additionally, they may be received by the device via an electromagnetic carrier signal and / or may be copied from a physical entity such as a computer program product. Execution of the computer readable instructions causes the device 1300 to perform one or more of the functions described above.

[0184] Memory 1320 may be implemented using any suitable data storage technology, such as semiconductor-based memory devices, flash memory, magnetic storage devices and systems, optical storage devices and systems, fixed memory, and / or removable memory. The memory may include a configuration database for storing configuration data. For example, the configuration database may store a list of current neighbor cells and, in some exemplary embodiments, a structure of frames used in detected neighbor cells.

[0185] The device 1300 may also include a communication interface 1330, which includes hardware and / or software for implementing communication connectivity according to one or more communication protocols. The communication interface 1330 includes at least one transmitter (Tx) and at least one receiver (Rx), which may be integrated into the device 1300 or the device 1300 may be connected to the transmitter (Rx). The communication interface 1330 may include one or more components, such as a power amplifier, a digital front end (DFE), an analog-to-digital converter or an analog-to-digital converter (ADC), a digital-to-analog converter (DAC), a frequency converter, a (de)modulator, and / or an encoder / decoder circuit, which are controlled by corresponding control units.

[0186] The communication interface 1330 provides the apparatus with radio communication capabilities for communicating in a cellular communication system. The communication interface may, for example, provide a radio interface to one or more user equipment. The apparatus 1300 may also include another interface toward a core network entity such as a network coordinator or AMF and / or an access node of the cellular communication system.

[0187] It should be noted that the device 1300 may also include Figure 13 Various components not shown in the figure may be hardware components and / or software components.

[0188] The term "circuitry" as used in this application may refer to one or more or all of the following: a) a hardware circuit implementation only (e.g. an implementation in analog and / or digital circuitry only); and b) a combination of hardware circuitry and software, such as (as applicable): i) a combination of analog and / or digital hardware circuitry and software / firmware; ii) any portion of a hardware processor together with software (including a digital signal processor, software and memory that work together to enable a device (e.g. a mobile phone) to perform various functions); and c) hardware circuitry and / or processors, such as a microprocessor or part of a microprocessor, that requires software (e.g. firmware) to operate, but may not be present when no software is required for operation.

[0189] This definition of circuitry applies to all uses of this term in this application, including in any claims. As a further example, as used in this application, the term circuitry also covers an implementation of merely a hardware circuit or processor (or multiple processors) or a portion of a hardware circuit or processor and its (or its) accompanying software and / or firmware. The term circuitry also covers, for example and if applicable to the particular claim element, a baseband integrated circuit or processor integrated circuit for a mobile device or a similar integrated circuit in a server, cellular network device, or other computing or networking device.

[0190] The techniques and methods described herein can be implemented in various ways. For example, these techniques can be implemented in hardware (one or more devices), firmware (one or more devices), software (one or more modules), or a combination thereof. For hardware implementation, the apparatus of the exemplary embodiments can be implemented in one or more application specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing devices (DSPDs), programmable logic devices (PLDs), field programmable gate arrays (FPGAs), graphics processing units (GPUs), processors, controllers, microcontrollers, microprocessors, other electronic units designed to perform the functions described herein, or a combination thereof. For firmware or software, it can be implemented by a module (e.g., a program, a function, etc.) of at least one chipset that performs the functions described herein. The memory unit can be implemented inside the processor or outside the processor.

[0191] In the latter case, it may be communicatively coupled to the processor by various means, as is known in the art. Furthermore, the components of the systems described herein may be rearranged and / or supplemented by additional components to facilitate implementation of various aspects thereof, etc., and they are not limited to the precise configurations set forth in a given figure, as will be understood by those skilled in the art.

[0192] It is obvious to those skilled in the art that, as technology advances, the concepts of the present invention may be implemented in various ways. The embodiments are not limited to the exemplary embodiments described above, but may vary within the scope of the claims. Therefore, all words and expressions should be interpreted broadly, and they are intended to illustrate, not to restrict, the exemplary embodiments.

Claims

1. An apparatus comprising at least one processor and at least one memory storing instructions that, when executed by the at least one processor, cause the apparatus to at least: Acquire a first set of measurement information associated with a reference signal sent from a set of positioning reference units; selecting a subset of positioning reference elements from the set of positioning reference elements, wherein the selection is based at least on: determining that the reference signal transmitted by each positioning reference element of the subset of positioning reference elements is measured by the same set of network nodes that measure the reference signal transmitted from the target user equipment, The subset of positioning reference units is further selected based on at least one of the following: comparing the time of flight of the reference signal transmitted by each positioning reference element of the positioning reference element subset with the time of flight of the reference signal transmitted from the target user equipment, or comparing the timing advance of each positioning reference unit of the positioning reference unit subset with the timing advance of the target user equipment; as well as A position estimate of the target user equipment is refined based on at least a subset of measurement information from the first measurement information set, wherein the subset of measurement information is associated with the subset of positioning reference units.

2. The apparatus according to claim 1 , further caused to: marking the one or more first network nodes based on a second set of measurement information reported from the one or more first network nodes being within one or more limits, wherein the second set of measurement information is associated with the reference signal sent from the target user equipment; for each positioning reference unit of the set of positioning reference units, marking the one or more second network nodes based on the first set of measurement information reported from the one or more second network nodes being within the one or more limits; for each positioning reference unit of the set of positioning reference units, comparing the identities of the one or more first network nodes with the one or more second network nodes; Based on the comparison of the identities, it is determined that the reference signal transmitted by each positioning reference element of the subset of positioning reference elements is measured by the same set of network nodes that measure the reference signal transmitted from the target user equipment.

3. The apparatus according to any preceding claim, further caused to: determining a time-of-flight value for each positioning reference unit of the subset of positioning reference units, wherein the time-of-flight value for each positioning reference unit indicates a difference between a time of departure of the reference signal transmitted from the positioning reference unit and a time of arrival of the reference signal transmitted from the positioning reference unit; determining a time-of-flight value for the target user equipment, wherein the time-of-flight value for the target user equipment indicates a difference between a departure time of the reference signal sent from the target user equipment and an arrival time of the reference signal sent from the target user equipment; comparing the time-of-flight value of the target user equipment with the time-of-flight value of each positioning reference unit; as well as removing the one or more positioning reference units from the positioning reference unit subset based on a difference between the flight time value of the target user equipment and the flight time values of the one or more positioning reference units being greater than a threshold, The measurement information subset is associated with the reference signal sent from the positioning reference unit subset from which the one or more positioning reference units are removed.

4. The apparatus according to any preceding claim, further caused to: Obtaining timing advance values allocated to the target user equipment by multiple network nodes; Obtaining timing advance values allocated to the set of positioning reference units by the plurality of network nodes; For each of the plurality of network nodes, comparing the timing advance value of the target user equipment with the timing advance value of the positioning reference unit set, The positioning reference unit subset is further selected based on the number of network nodes for which the timing advance value of the positioning reference unit subset is within a predefined interval compared to the timing advance value of the target user equipment.

5. The apparatus of any preceding claim, wherein the reference signals sent from the target user equipment and the set of positioning reference elements are uplink sounding reference signals.

6. An apparatus as claimed in any preceding claim, wherein the apparatus comprises or is comprised in a location management function.

7. A method comprising: Acquire a first set of measurement information associated with a reference signal sent from a set of positioning reference units; selecting a subset of positioning reference elements from the set of positioning reference elements, wherein the selection is based at least on: determining that the reference signal transmitted by each positioning reference element of the subset of positioning reference elements is measured by the same set of network nodes that measure the reference signal transmitted from the target user equipment, The subset of positioning reference units is further selected based on at least one of the following: comparing the time of flight of the reference signal transmitted by each positioning reference element of the positioning reference element subset with the time of flight of the reference signal transmitted from the target user equipment, or comparing the timing advance of each positioning reference unit of the positioning reference unit subset with the timing advance of the target user equipment; as well as A position estimate of the target user equipment is refined based on at least a subset of measurement information from the first measurement information set, wherein the subset of measurement information is associated with the subset of positioning reference units.

8. The method according to claim 7, further comprising: marking the one or more first network nodes based on a second set of measurement information reported from the one or more first network nodes being within one or more limits, wherein the second set of measurement information is associated with the reference signal sent from the target user equipment; for each positioning reference unit of the set of positioning reference units, marking the one or more second network nodes based on the first set of measurement information reported from the one or more second network nodes being within the one or more limits; for each positioning reference unit of the set of positioning reference units, comparing the identities of the one or more first network nodes with the one or more second network nodes; Based on the comparison of the identities, it is determined that the reference signal transmitted by each positioning reference element of the subset of positioning reference elements is measured by the same set of network nodes that measure the reference signal transmitted from the target user equipment.

9. The method according to any one of claims 7-8, further comprising: determining a time-of-flight value for each positioning reference unit of the subset of positioning reference units, wherein the time-of-flight value for each positioning reference unit indicates a difference between a time of departure of the reference signal transmitted from the positioning reference unit and a time of arrival of the reference signal transmitted from the positioning reference unit; determining a time-of-flight value for the target user equipment, wherein the time-of-flight value for the target user equipment indicates a difference between a departure time of the reference signal sent from the target user equipment and an arrival time of the reference signal sent from the target user equipment; comparing the time-of-flight value of the target user equipment with the time-of-flight value of each positioning reference unit; as well as removing the one or more positioning reference units from the positioning reference unit subset based on a difference between the flight time value of the target user equipment and the flight time values of the one or more positioning reference units being greater than a threshold, The measurement information subset is associated with the reference signal sent from the positioning reference unit subset from which the one or more positioning reference units are removed.

10. The method according to any one of claims 7 to 9, further comprising: Obtaining timing advance values allocated to the target user equipment by multiple network nodes; Obtaining timing advance values allocated to the set of positioning reference units by the plurality of network nodes; For each of the plurality of network nodes, comparing the timing advance value of the target user equipment with the timing advance value of the positioning reference unit set, The positioning reference unit subset is further selected based on the number of network nodes for which the timing advance value of the positioning reference unit subset is within a predefined interval compared to the timing advance value of the target user equipment.

11. The method according to any one of claims 7 to 10, wherein the reference signals sent from the target user equipment and the positioning reference element set are uplink sounding reference signals.

12. The method according to any one of claims 7 to 11, wherein the method is performed by a location management function.

13. A non-transitory computer-readable medium comprising program instructions that, when executed by an apparatus, cause the apparatus to at least: Acquire a first set of measurement information associated with a reference signal sent from a set of positioning reference units; selecting a subset of positioning reference elements from the set of positioning reference elements, wherein the selection is based at least on: determining that the reference signal transmitted by each positioning reference element of the subset of positioning reference elements is measured by the same set of network nodes that measure the reference signal transmitted from the target user equipment, The subset of positioning reference units is further selected based on at least one of the following: comparing the time of flight of the reference signal transmitted by each positioning reference element of the positioning reference element subset with the time of flight of the reference signal transmitted from the target user equipment, or comparing the timing advance of each positioning reference unit of the positioning reference unit subset with the timing advance of the target user equipment; as well as A position estimate of the target user equipment is refined based on at least a subset of measurement information from the first measurement information set, wherein the subset of measurement information is associated with the subset of positioning reference units.

14. A system comprising at least a location management function and a user device; The user equipment is configured as follows: Initiating an activation procedure to activate one or more positioning reference units for a positioning session of the user equipment, wherein the activation procedure is initiated based on at least one of: a radio resource control state of the user equipment, a number of detected network nodes, or a number of detected positioning reference units; The location management function is configured to: Acquire a first set of measurement information associated with a reference signal sent from a set of positioning reference units; selecting a subset of positioning reference units from the set of positioning reference units, wherein the selection is based at least on: determining that the reference signal transmitted by each positioning reference unit of the subset of positioning reference units is measured by the same set of network nodes that measure the reference signal transmitted from the user equipment, The subset of positioning reference units is further selected based on at least one of the following: comparing the time of flight of the reference signal transmitted by each positioning reference element of the positioning reference element subset with the time of flight of the reference signal transmitted from the target user equipment, or comparing the timing advance of each positioning reference unit of the positioning reference unit subset with the timing advance of the target user equipment; as well as A position estimate of the user equipment is refined based on at least a subset of measurement information from the first measurement information set, wherein the subset of measurement information is associated with the subset of positioning reference units.

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