Reference information for reference signal time difference

Abstract

Disclosed is a method comprising: selecting at least one user equipment from one or more candidate user equipment as a reference for reference signal time difference (RSTD) measurement; measuring the RSTD between at least two reference signals, the at least two reference signals including at least a sidelink positioning reference signal received from at least one user equipment selected as a reference; and transmitting a report to a network element of the core network, the report comprising at least one of: an identifier of at least one user equipment selected as a reference for RTSD measurement, an identifier of a resource associated with a sidelink positioning reference signal received from the at least one user equipment, the synchronization source information indicates at least one synchronization source of the at least one user equipment, or a timestamp of a sidelink positioning reference signal received from the at least one user equipment.

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 in order to more accurately estimate the location of a device. Summary of the invention

[0003] The scope of protection sought by various example embodiments is set forth by the independent claims. Example embodiments and features described in this specification that do not fall under the scope of the independent claims, if any, are to be construed as examples to aid in the understanding of the various embodiments.

[0004] According to one aspect, a device in a radio access network is provided, the device comprising at least one processor and at least one memory storing instructions, the instructions, when executed by the at least one processor, causing the device to at least: select at least one user equipment from one or more candidate user equipment as a reference for reference signal time difference (RSTD) measurement; measure RSTD between at least two reference signals, wherein the at least two reference signals include at least a secondary link positioning reference signal received from at least one user equipment selected as a reference; and send a report to a network unit of a core network, the report including at least one of the following: an identifier of at least one user equipment selected as a reference for RTSD measurement, an identifier of a resource associated with the secondary link positioning reference signal received from the at least one user equipment, synchronization source information indicating at least one synchronization source of the at least one user equipment, or a timestamp of the secondary link positioning reference signal received from the at least one user equipment.

[0005] According to another aspect, a device in a radio access network is provided, the device comprising: a component for selecting at least one user equipment from one or more candidate user equipment as a reference for reference signal time difference (RSTD) measurement; a component for measuring RSTD between at least two reference signals, wherein the at least two reference signals include at least a sub-link positioning reference signal received from at least one user equipment selected as a reference; and a component for sending a report to a network unit of a core network, wherein the report comprises at least one of the following: an identifier of at least one user equipment selected as a reference for RTSD measurement, an identifier of a resource associated with the sub-link positioning reference signal received from the at least one user equipment, synchronization source information indicating at least one synchronization source of the at least one user equipment, or a timestamp of the sub-link positioning reference signal received from the at least one user equipment.

[0006] According to another aspect, a method is provided, comprising: selecting, by a device in a radio access network, at least one user equipment from one or more candidate user equipment as a reference for reference signal time difference (RSTD) measurement; measuring, by the device, the RSTD between at least two reference signals, wherein the at least two reference signals include at least a sub-link positioning reference signal received from at least one user equipment selected as a reference; and sending, by the device, a report to a network unit of a core network, the report comprising at least one of: an identifier of at least one user equipment selected as a reference for RTSD measurement, an identifier of a resource associated with the sub-link positioning reference signal received from the at least one user equipment, synchronization source information indicating at least one synchronization source of the at least one user equipment, or a timestamp of the sub-link positioning reference signal received from the at least one user equipment.

[0007] According to another aspect, a computer program is provided comprising instructions which, when executed by an apparatus in a radio access network, cause the apparatus to perform at least the following operations: select at least one user equipment from one or more candidate user equipment as a reference for reference signal time difference (RSTD) measurement; measure RSTD between at least two reference signals, wherein the at least two reference signals include at least a sub-link positioning reference signal received from at least one user equipment selected as a reference; and send a report to a network unit of a core network, the report comprising at least one of the following: an identifier of at least one user equipment selected as a reference for RTSD measurement, an identifier of a resource associated with the sub-link positioning reference signal received from the at least one user equipment, synchronization source information indicating at least one synchronization source of the at least one user equipment, or a timestamp of the sub-link positioning reference signal received from the at least one user equipment.

[0008] According to another aspect, a computer-readable medium comprising program instructions is provided, which, when executed by an apparatus in a radio access network, causes the apparatus to perform at least the following operations: select at least one user equipment from one or more candidate user equipment as a reference for reference signal time difference (RSTD) measurement; measure RSTD between at least two reference signals, wherein the at least two reference signals include at least a sub-link positioning reference signal received from at least one user equipment selected as a reference; and send a report to a network unit of a core network, the report comprising at least one of the following: an identifier of at least one user equipment selected as a reference for RTSD measurement, an identifier of a resource associated with the sub-link positioning reference signal received from the at least one user equipment, synchronization source information indicating at least one synchronization source of the at least one user equipment, or a timestamp of the sub-link positioning reference signal received from the at least one user equipment.

[0009] According to another aspect, a non-transitory computer-readable medium comprising program instructions is provided, which, when executed by an apparatus in a radio access network, causes the apparatus to perform at least the following operations: select at least one user equipment from one or more candidate user equipment as a reference for reference signal time difference (RSTD) measurement; measure RSTD between at least two reference signals, wherein the at least two reference signals include at least a sub-link positioning reference signal received from at least one user equipment selected as a reference; and send a report to a network unit of a core network, the report comprising at least one of the following: an identifier of at least one user equipment selected as a reference for RTSD measurement, an identifier of a resource associated with the sub-link positioning reference signal received from the at least one user equipment, synchronization source information indicating at least one synchronization source of the at least one user equipment, or a timestamp of the sub-link positioning reference signal received from the at least one user equipment.

[0010] According to one aspect, a device in a core network is provided, the device comprising at least one processor and at least one memory storing instructions, the instructions, when executed by the at least one processor, causing the device to at least: receive a report from a target user equipment, the report comprising at least one of the following: an identifier of at least one user equipment selected as a reference for measuring a reference signal time difference RSTD, an identifier of a resource associated with a secondary link positioning reference signal used to measure RSTD, synchronization source information indicating at least one synchronization source of at least one user equipment selected as a reference for measuring RSTD, or a timestamp of the secondary link positioning reference signal used to measure RSTD; and estimate the position of the target user equipment based at least in part on the report.

[0011] According to another aspect, a device in a core network is provided, the device comprising: a component for receiving a report from a target user equipment, wherein the report comprises at least one of the following: an identifier of at least one user equipment selected as a reference for measuring a reference signal time difference RSTD, an identifier of a resource associated with a sub-link positioning reference signal used to measure RSTD, synchronization source information indicating at least one synchronization source of at least one user equipment selected as a reference for measuring RSTD, or a timestamp of the sub-link positioning reference signal used to measure RSTD; and a component for estimating the position of the target user equipment based at least in part on the report.

[0012] According to another aspect, a method is provided, comprising: receiving, by a device in a core network, a report from a target user equipment, the report comprising at least one of: an identifier of at least one user equipment selected as a reference for measuring a reference signal time difference RSTD, an identifier of a resource associated with a sub-link positioning reference signal used to measure RSTD, synchronization source information indicating at least one synchronization source of at least one user equipment selected as a reference for measuring RSTD, or a timestamp of the sub-link positioning reference signal used to measure RSTD; and estimating, by the device at least partially based on the report, a position of the target user equipment.

[0013] According to another aspect, a computer program is provided comprising instructions which, when executed by an apparatus in a core network, cause the apparatus to perform at least the following operations: receive a report from a target user equipment, the report comprising at least one of: an identifier of at least one user equipment selected as a reference for measuring a reference signal time difference RSTD, an identifier of a resource associated with a secondary link positioning reference signal used to measure RSTD, synchronization source information indicating at least one synchronization source of at least one user equipment selected as a reference for measuring RSTD, or a timestamp of the secondary link positioning reference signal used to measure RSTD; and estimate the position of the target user equipment based at least in part on the report.

[0014] According to another aspect, a computer-readable medium comprising program instructions is provided, which, when executed by an apparatus in a core network, causes the apparatus to perform at least the following operations: receive a report from a target user equipment, the report comprising at least one of the following: an identifier of at least one user equipment selected as a reference for measuring a reference signal time difference RSTD, an identifier of a resource associated with a sub-link positioning reference signal used to measure RSTD, synchronization source information indicating at least one synchronization source of at least one user equipment selected as a reference for measuring RSTD, or a timestamp of the sub-link positioning reference signal used to measure RSTD; and estimate the position of the target user equipment based at least in part on the report.

[0015] According to another aspect, a non-transitory computer-readable medium comprising program instructions is provided, which, when executed by an apparatus in a core network, causes the apparatus to perform at least the following operations: receive a report from a target user equipment, the report comprising at least one of the following: an identifier of at least one user equipment selected as a reference for measuring a reference signal time difference RSTD, an identifier of a resource associated with a secondary link positioning reference signal used to measure RSTD, synchronization source information indicating at least one synchronization source of at least one user equipment selected as a reference for measuring RSTD, or a timestamp of the secondary link positioning reference signal used to measure RSTD; and estimate the position of the target user equipment based at least in part on the report.

[0016] According to one aspect, a device in a radio access network is provided, the device comprising at least one processor and at least one memory storing instructions, the instructions, when executed by the at least one processor, causing the device to at least: receive a threshold for the time difference between receiving a downlink positioning reference signal and sending a sub-link positioning reference signal from a network unit of a core network; and send a sub-link positioning reference signal to a target user equipment based at least on the threshold, wherein the time difference between receiving the downlink positioning reference signal and sending the sub-link positioning reference signal is less than the threshold.

[0017] According to another aspect, a device in a radio access network is provided, the device comprising: a component for receiving a threshold for the time difference between receiving a downlink positioning reference signal and sending a sub-link positioning reference signal from a network unit of a core network; and a component for sending a sub-link positioning reference signal to a target user equipment based at least on the threshold, wherein the time difference between receiving the downlink positioning reference signal and sending the sub-link positioning reference signal is less than the threshold.

[0018] According to another aspect, a method is provided, comprising: receiving, by a device in a radio access network, a threshold for the time difference between receiving a downlink positioning reference signal and sending a sub-link positioning reference signal from a network unit of a core network; and sending, by the device at least based on the threshold, a sub-link positioning reference signal to a target user equipment, wherein the time difference between receiving the downlink positioning reference signal and sending the sub-link positioning reference signal is less than the threshold.

[0019] According to another aspect, a computer program is provided comprising instructions which, when executed by a device in a radio access network, cause the device to perform at least the following operations: receive a threshold for the time difference between receiving a downlink positioning reference signal and sending a sub-link positioning reference signal from a network unit of a core network; and send a sub-link positioning reference signal to a target user equipment based at least on the threshold, wherein the time difference between receiving the downlink positioning reference signal and sending the sub-link positioning reference signal is less than the threshold.

[0020] According to another aspect, a computer-readable medium comprising program instructions is provided, which, when executed by an apparatus in a radio access network, causes the apparatus to perform at least the following operations: receive a threshold for the time difference between receiving a downlink positioning reference signal and sending a sub-link positioning reference signal from a network unit of a core network; and send a sub-link positioning reference signal to a target user equipment based at least on the threshold, wherein the time difference between receiving the downlink positioning reference signal and sending the sub-link positioning reference signal is less than the threshold.

[0021] According to another aspect, a non-transitory computer-readable medium comprising program instructions is provided, which, when executed by an apparatus in a radio access network, causes the apparatus to perform at least the following operations: receive a threshold for the time difference between receiving a downlink positioning reference signal and sending a sub-link positioning reference signal from a network unit of a core network; and send a sub-link positioning reference signal to a target user equipment based at least on the threshold, wherein the time difference between receiving the downlink positioning reference signal and sending the sub-link positioning reference signal is less than the threshold. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Various example embodiments will be described in more detail below with reference to the accompanying drawings, in which:

[0023] Figure 1 An example of a cellular communication network is shown;

[0024] Figure 2 An example showing the time difference of arrival from a secondary link positioning reference signal and a downlink positioning reference signal;

[0025] Figure 3 shows a signaling diagram according to an example embodiment;

[0026] Figure 4 shows a signaling diagram according to an example embodiment;

[0027] Figure 5 shows a signaling diagram according to an example embodiment;

[0028] Figure 6 shows a flow chart according to an example embodiment;

[0029] Figure 7 shows a flow chart according to an example embodiment;

[0030] Figure 8 shows a flow chart according to an example embodiment;

[0031] Fig. 9 An example of an apparatus is shown; and

[0032] Fig.10 An example of a device is shown. DETAILED DESCRIPTION

[0033] The following embodiments are exemplary. Although this specification may refer to "one", "an" or "some" embodiments at several locations in the text, this does not necessarily mean that each reference is to the same embodiment, nor does it mean that a particular feature applies only to a single embodiment. Individual features of different embodiments may also be combined to provide other embodiments.

[0034] In the following, different example embodiments will be described using a radio access architecture based on Advanced Long Term Evolution (LTE-Advanced, LTE-A), New Radio (NR, 5G), Beyond 5G, or Sixth Generation (6G) as an example of an access architecture to which the example embodiments may be applied, but the example embodiments are not limited to such architectures. It will be apparent to a person skilled in the art that the example embodiments may also be applied to other kinds of communication networks with suitable components by appropriately adjusting the parameters and procedures. Some examples of other options for suitable systems may be Universal Mobile Telecommunications System (UMTS) Radio Access Network (UTRAN or E-UTRAN), Long Term Evolution (LTE, which is basically the same as E-UTRA), Wireless Local Area Network (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 (MANETs), and Internet Protocol Multimedia Subsystem (IMS), or any combination thereof.

[0035] Figure 1 An example of a simplified system architecture is depicted showing some units / elements and functional entities, which are all logical units, the implementation of which may differ from what is shown. Figure 1 The connections shown in are logical connections; the actual physical connections may be different. It is obvious to those skilled in the art that the system may also include Figure 1 Other functions and structures than those shown in .

[0036] 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 characteristics.

[0037] Figure 1 The example of FIG. 1 shows a portion of an exemplary radio access network.

[0038] Figure 1 User equipment 100 and 102 are shown, which are configured to wirelessly connect to 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)) providing the radio cell on one or more communication channels in 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 a side link (SL) communication. It should be understood that the access node or its functions can be implemented by using any node, host, server or access point entity suitable for such use.

[0039] The 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 may be used to route data from one access node to another access node. 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 or be coupled to a transceiver. A connection to an antenna unit may be provided from the transceiver of the access node, which establishes a two-way radio link to a user device. 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 counterpart to which the access node on the CN side can be connected 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 connection to an external packet data network, a user plane function (UPF), a mobility management entity (MME), or an access and mobility management function (AMF), etc.

[0040] Regarding positioning, the service-based architecture (core network) may include an AMF 111 and a location management function (LMF) 112. The AMF may provide location information for call processing, policies, and billing to other network functions in the core network and to other entities requesting the positioning of terminal devices. The AMF may receive and manage positioning requests from several sources: mobile initiated positioning requests (MO-LR) from user equipment and mobile terminated positioning requests (MT-LR) from other functions of the core network or from other network elements. The AMF may select an LMF for a given request and use its positioning service to trigger a positioning session. In turn, the LMF may perform positioning after receiving such a request from the AMF. The LMF may manage the resources and timing of positioning activities. The LMF may request the positioning of the user equipment from one or more access nodes using the Namf_Communication service on the NL1 interface, or the LMF may communicate with the user equipment on N1 for UE-based or UE-assisted positioning. Positioning may include an estimate of the location, and additionally, the LMF may also estimate the mobility or accuracy of the location information when requested. In terms of connection, the AMF may be between the access node and the LMF and therefore be closer to the access node than the LMF.

[0041] A user equipment illustrates one type of apparatus to which resources on an air interface may be allocated and assigned, and thus any features of a user equipment described herein may be implemented with a corresponding apparatus, such as a relay node.

[0042] An example of such a relay node may be a layer 3 relay towards an access node (self-backhauled relay). A self-backhauled 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 termination (MT) part, which is responsible for the backhaul link (i.e., the link between the IAB node and a donor node (also referred to as a parent node)); and a distributed unit (DU) part, which is responsible for the access link (i.e., the sub-link between the IAB node and a user equipment and / or between an IAB node and other IAB nodes (multi-hop scenario)).

[0043] Another example of such a relay node may be a layer 1 repeater (referred to as a repeater). The repeater 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.

[0044] 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 mention only a few names or devices. User equipment may refer to a portable computing device including a wireless mobile communication device operating with or without a subscriber identity module (SIM), including but not limited to the following types of devices: mobile station (mobile phone), smart phone, personal digital assistant (PDA), mobile phone, device using a wireless modem (alarm or measurement device, etc.), laptop and / or touch screen computer, tablet computer, game console, notebook computer, multimedia device, reduced functionality (RedCap) device, wireless sensor device, or any device integrated in a vehicle.

[0045] It should be understood that the user device can also be a nearly exclusive uplink-only device, an example of which can be a camera or video camera that loads images or video clips to the network. The user device can also be a device with the ability to operate in an Internet of Things (IoT) network, which is a scenario in which an object can be provided with the ability to transmit data over a network without the need for human-to-human or human-to-computer interaction. The user device can also utilize the cloud. In some applications, the user device can include a small portable or wearable device (such as a watch, headset, or glasses) with a radio portion, and can perform calculations in the cloud or in another user device. The user device (or in some example embodiments, a layer 3 relay node) can be configured to perform one or more user device functions.

[0046] The various techniques described herein may also be applied to cyber-physical systems (CPS) (systems of cooperating computing elements that control physical entities). CPS may 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 system in question may have inherent mobility) are a subcategory of cyber-physical systems. Examples of mobile physical systems include mobile robots and electronic devices transported by humans or animals.

[0047] Furthermore, although the apparatus is described as a single entity, different units, processors and / or memory units may be implemented. Figure 1 not all are shown).

[0048] 5G enables the use of multiple-input multiple-output (MIMO) antennas, more base stations or nodes than LTE (the so-called small cell concept), including macro sites that operate in collaboration with smaller stations and adopt various 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 (i.e., below 6GHz, centimeter wave (cmWave) and millimeter wave (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 in which macro coverage can be provided by LTE, and 5G radio interface access can come from a small cell through aggregation to LTE. In other words, 5G can support both inter-RAT operability (such as LTE-5G) and inter-RI operability (inter-radio interface operability, such as below 6GHz-cmWave-mmWave). One of the concepts being considered for use in 5G networks could be network slicing, where 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.

[0049] The current architecture in LTE networks can be completely distributed in the radio and completely concentrated in the core network. Low-latency applications and services in 5G may require content to be close to the radio, resulting in local grooming and multi-access edge computing (MEC). 5G may enable analysis and knowledge generation to be performed at the data source. This approach may require the use of resources that may not be continuously connected to the network, such as laptops, smart phones, tablets, and sensors. MEC can provide a distributed computing environment for application and service hosting. It can also be able to store and process content at locations close to cellular users to achieve faster response times. Edge computing can cover a wide range of technologies, such as wireless sensor networks, mobile data acquisition, mobile signature analysis, collaborative distributed peer-to-peer self-organizing networking and processing (also classified as local cloud / fog computing and grid / mesh computing, dew computing, mobile edge computing, cloudlet, distributed data storage and retrieval), autonomous self-healing networks, remote cloud services, augmented reality and virtual reality, data caching, the Internet of Things (large-scale connection and / or delay critical), critical communications (autonomous driving vehicles, traffic safety, real-time analysis, time-critical control, healthcare applications).

[0050] The communication system may also be capable of communicating with, or using services provided by, one or more other networks 113, such as a public switched telephone network or the Internet. The communication network may also be capable of supporting the use of cloud services, for example, at least a portion of the core network operations may be provided as a cloud service (this is in the context of Figure 1 The communication system may also include a central control entity or the like, providing facilities for networks of different operators to collaborate, for example, in spectrum sharing.

[0051] Edge cloud can be introduced into the radio access network (RAN) by utilizing network function virtualization (NFV) and software defined networking (SDN). Using edge cloud can mean performing access node operations at least partially in a server, host or node of an access node that is operably coupled to a remote radio head (RRH) or a radio unit (RU) or includes a radio part. Node operations can also be distributed among multiple servers, nodes, or hosts. The application of cloudRAN architecture enables RAN real-time functions to be performed on the RAN side (in the distributed unit DU 105) and non-real-time functions to be performed in a centralized manner (in the centralized unit CU 108).

[0052] It should also be understood that the functional distribution between core network operations and access node operations may be different from LTE or even non-existent. Some other technological advances 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.

[0053] 5G can also leverage non-terrestrial communications (e.g., satellite communications) to enhance or supplement the coverage of 5G services, for example by providing backhaul. Possible use cases could be to provide service continuity for machine-to-machine (M2M) or Internet of Things (IoT) devices or onboard passengers, or to ensure service availability for critical communications and future rail / maritime / aviation communications. Satellite communications can leverage geostationary orbit (GEO) satellite systems, as well as low earth orbit (LEO) satellite systems, in particular mega-constellations (systems in which hundreds of (nano) satellites are deployed). A given satellite 106 in a mega-constellation can cover several satellite-supporting 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.

[0054] 6G networks are expected to adopt flexible decentralized and / or distributed computing systems and architectures and ubiquitous computing, with local spectrum licensing, spectrum sharing, infrastructure sharing, and intelligent automated management, based on mobile edge computing, artificial intelligence, short packet communications, and blockchain technologies. Key features of 6G may include intelligent connection management and control capabilities, programmability, integrated sensing and communications, reduced energy footprint, trusted infrastructure, scalability, and affordability. In addition to this, 6G targets new use cases, which include integrating positioning and sensing capabilities into system definitions to unify user experience in the physical and digital worlds.

[0055] It is obvious to a person skilled in the art that the depicted system is only an example of a part of a radio access system, and in practice, the system may include multiple access nodes, a user equipment may access 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 / home eNodeB or a home / home gNodeB.

[0056] In addition, the access node can also be divided into: a radio unit (RU), which includes 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 referred to as a centralized unit), which can be used for non-real-time L2 and layer 3 (L3) processing. The CU can be connected to one or more DUs, for example, by using an F1 interface. This division can enable the CU to be centralized relative to the cell site and the DU, while the DU can be more decentralized and can even be retained at the cell site. The CU and DU can also be collectively referred to as a baseband or baseband unit (BBU). The CU and DU can also be included in a radio access point (RAP).

[0057] The CU may be defined as a logical node that hosts 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 hosts the radio link control (RLC), media access control (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 hosts the RRC and the control plane portion of the CU's PDCP protocol for the access node. The CU may also include a user plane (CU-UP), which may be defined as a logical node that hosts the CU's PDCP protocol and the user plane portion of the SDAP protocol for the access node.

[0058] The cloud computing platform can also be used to run 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, a virtualized DU (vDU) can also run 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 access node units mentioned above or between different core network operations and access node operations may be different.

[0059] Furthermore, in a geographical area of ​​a radio communication system, a plurality of different kinds of radio cells and 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 up to tens of kilometres in diameter, or a smaller cell such as a micro cell, a femto cell or a pico cell. Figure 1 An access node may provide any of these cells. A cellular radio system may be implemented as a multi-layer network comprising several radio cells. In a multi-layer network, one access node may provide one or more radio cells of one type, and therefore multiple access nodes may be required to provide such a network structure.

[0060] 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. In addition to the home / home eNodeB or home / home gNodeB, a network that can use "plug and play" access nodes can also include a home / home NodeB gateway or HNB-GW ( Figure 1 (not shown). The HNB-GW (which may be installed within the operator's network) may aggregate traffic from a large number of home / home eNodeBs or home / home gNodeBs back to the core network.

[0061] Positioning technology can be used to estimate the physical location of user equipment. In this article, the user equipment to be located is referred to as the target UE or target user equipment. In wireless positioning, multiple positioning anchor points in a known position 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-point positioning technique can be used to find the position of the target UE relative to the positioning anchor point (i.e., locate the target UE). In this article, the positioning anchor point can also be referred to as an anchor point, an anchor node, a multi-point positioning anchor point, or a reference point. The positioning anchor point can be, for example, a radio access node (in uplink / downlink positioning), a transmit and receive point (TRP) (in uplink / downlink positioning), or other UEs (in secondary link positioning).

[0062] Side-link (SL) positioning refers to a positioning method in which the target UE utilizes a side-link (i.e., PC5 interface) to locate itself in an absolute manner (in the case of absolute positioning, where 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, where the position of the target UE is estimated relative to another entity (e.g., another non-static or anchor UE)). For UE-assisted positioning, the target UE utilizes the side-link to obtain positioning measurements and reports these measurements to a network entity (such as a location management function (LMF)). Side-link 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).

[0063] Sidelink positioning involves the use of a supporting UE or a group of supporting UEs (referred to as "anchor UEs") that assist a positioning session of a target UE. Anchor UE support may be achieved in various ways, including the anchor UE estimating the position of the target UE, the anchor UE providing positioning assistance data to the target UE on a sidelink, and / or the anchor UE sending and / or receiving reference signals (such as sidelink positioning reference signals (SL PRS)) to and / or from the target UE for positioning purposes.

[0064] SL PRS is a reference signal sent on the secondary link for positioning purposes. The SL PRS (pre) configuration may include at least one (pre) configuration parameter of the SL PRS, such as time-frequency resources (including its bandwidth), periodicity, an identifier associated with a secondary link positioning reference signal resource, and an identifier associated with a set of secondary link positioning reference signal resources (not excluding other parameters).

[0065] For example, the following positioning techniques may be used in 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). Both RAT-dependent and RAT-independent NR positioning techniques may be used. RAT is an abbreviation for Radio Access Technology.

[0066] DL-TDOA and UL-TDOA have been introduced in NR Release 16 and further enhanced in NR Release 17. DL-TDOA technology relies on measuring the reference signal time difference (RSTD) of DL positioning reference signals sent from multiple TRP locations, and UL-TDOA technology relies on relative time of arrival (RTOA) measurements measured at multiple TRP locations in order to perform trilateration and estimate the location of the target UE. One disadvantage of TDOA technology is that it requires tight synchronization between TRPs to obtain high positioning accuracy.

[0067] As mentioned above, DL-TDOA relies on RSTD measurements, where the target UE measures the relative time of arrival to a reference. Reporting for this measurement can be seen in the NR Release 17 specification (TS.37.335) as follows:

[0068]

[0069] From the above content, it can be seen that the measurement report of DL-TDOA depends on dl-PRS-ReferenceInfo-r16 and the resource ID or resource set ID of another PRS.

[0070] NR Release 16 / 17 positioning supports DL-TDOA technology based on DL PRS. DL-TDOA technology may require the target UE to measure multiple RSTD measurements from multiple TRPs and / or cells, and it may require a single reference to calculate RSTD. In NR Release 16 / 17, a single reference timing is determined based on a specific TRP, PRS resource set, and / or PRS resource.

[0071] In NR Release 18, the TDOA technique can be based on either or both of the SL PRS and DL PRS. However, the current specification is not sufficient to support a mix of sidelink arrival time difference (SL-TDOA) techniques that can be measured using RSTD based on SL PRS and DL PRS. In addition, it is not sufficient to support SL-TDOA techniques that can be measured using RSTD based on two SL PRS sent from two different UEs. These measurements may also be referred to as SL RSTD measurements, TDOA measurements, or SL TDOA measurements. For example, without making any changes to the specification, the target UE will not be able to use SL PRS as a reference for RSTD measurements. As a result, the target UE will report the RSTD of the DL PRS and then report another RSTD of the SL PRS. In the absence of an RSTD between a reference DL PRS and a reference SL PRS, all reported RSTDs may not be used in one positioning estimate.

[0072] Some example embodiments may provide configuration and reporting of reference information for RSTD measurements to support TDOA based on DL PRS and SL PRS. Reference information may be required to support DL-TDOA and higher layer signaling "dl-PRS-ReferenceInfo-r16" introduced in NR Release 16.

[0073] Some example embodiments may provide support for SL-TDOA on SL PRS, and support for hybrid SL-TDOA on SL PRS and DL PRS.

[0074] It should be noted that RSTD may also be referred to as TDOA, but for simplicity, it is referred to as RSTD in this document.

[0075] Some example embodiments are described below using the principles and terminology of 5G technology; however, the example embodiments are not limited to 5G communication systems.

[0076] In some example embodiments, the target UE measures RSTD from specific DL PRS resources and SL PRS resources. The LMF may or may not configure SL PRS resources. However, the target UE may use a different reference configured for RSTD than the LMF so that the target UE selects an anchor UE and the SL PRS resources sent from the anchor UE for RSTD measurement reporting. In addition, the target UE may be able to use one or more RSTD references and report the reference information.

[0077] If the target UE uses a single RSTD reference, the LMF can run the position estimation algorithm with a single reference. The LMF may request the target UE to use a single RSTD reference for hybrid SL-TDOA based on SL-PRS and DL-PRS resources. The LMF may instruct the target UE to use the RSTD reference from the anchor UE and / or the SL PRS resources sent from the anchor UE, which have specific synchronization sources, and other synchronization sources may not be allowed (for example, the SL-UE may be allowed to use the gNB as its synchronization source, but the SL-UE may not be allowed to use the global navigation satellite system as its synchronization source). In this document, the SL-UE may refer to the anchor UE that sends the SL PRS used as a reference for RSTD measurement. The target UE may report the reference information used, which includes at least one of the following: a specific anchor UE ID, a SL-PRS resource ID, the synchronization source information of the anchor UE (for example, a cell ID or a global navigation satellite system), a specific timestamp about the SL-PRS resource ID sent by the anchor UE, and / or the position of the anchor UE at the timestamp (if the target UE knows it). If the target UE does not provide the location information of the anchor UE, the LMF may need a timestamp to determine the location of the anchor UE at a specific time.

[0078] For example, the target UE may report reference information including at least one of: 1) anchor UE ID, or 2) anchor UE ID and SL-PRS resource ID sent from the anchor UE. In addition, if one or more SL PRS resource sets are configured, the target UE may report reference information including at least the following items: anchor UE ID, SL PRS resource set ID, and SL PRS resource ID, wherein the SL PRS resources are included in the SL PRS resource set and are sent from the anchor UE. The reported reference information may also include synchronization source information and / or a timestamp.

[0079] As an example, let us assume that the LMF requests the target UE to use the SL-UE with synchronization source of gNB#2 as RSTD reference, and the synchronization source of the SL-UE (e.g., labeled as UE#1) is gNB#2. The SL-UE with synchronization source of gNB#2 means that the SL-UE is synchronized to gNB#2. In this case, the target UE can report the following RSTD measurements: RSTD from TRP#1 and UE#1, RSTD from TRP#2 and UE#1, and RSTD from UE#2 and UE#1. Note that TRP#1 and / or TRP#2 can be in gNB#2 or in different gNBs. If these TRP#1 and TRP#2 are in gNB#1, the LMF can compensate for the time synchronization error between gNB#1 and gNB#2 for RSTD measurements. As RSTD reference information, the target UE can report at least one of the following: SL-PRS resource, ID of UE#1, and / or timestamp of SL-PRS transmission from UE#1.

[0080] If the target UE uses multiple RSTD references, the LMF may need to run the position estimation algorithm multiple times with different references. The UE may be allowed to use multiple RSTD references for hybrid SL-TDOA based on SL-PRS and DL-PRS resources. The LMF may instruct the target UE to use one or more RSTD references from SL PRS resources with a specific synchronization source, but the LMF may provide a list of synchronization sources allowed for RSTD references. For example, a SL-UE using PCI#1 and PCI#2 as synchronization sources may be allowed for RSTD references. PCI is an abbreviation for physical cell identifier. The target UE may report the reference information used, which includes a specific anchor UE ID, SL-PRS resource ID, synchronization source information of the anchor UE (e.g., cell ID or global navigation satellite system), a specific timestamp of the SL-PRS resource ID sent by the anchor UE, and the position of the anchor UE at the timestamp (if the target UE knows it). If the target UE does not provide the location information of the anchor UE, the LMF may need a timestamp to determine the location of the anchor UE at a specific time. This report on RSTD reference information may also be reported in addition to the current report on RSTD reference. For example, the target UE may be able to report two RSTD references so that it can report the TRP ID (e.g., TRP#1), the PRS resource set ID, and / or the PRS resource ID through high-layer signaling (e.g., "dl-PRS-ReferenceInfo-r16"), and it may also report the anchor UE's ID (e.g., the UE#1's ID), the SL-PRS resource ID, the synchronization source information (e.g., the cell ID), and the timestamp. Note that this timestamp does not mean the measurement time for the DL PRS, but means the measurement time of the SL-PRS resource.

[0081] As an example, let us assume that the target UE measures the following RSTD measurements and reports them to the LMF as described below with reference to Figure 2 as described.

[0082] Figure 2 An example of TDOA from SL PRS and DL PRS is illustrated. In this example, the first TRP 211 (TRP#1) can send a first DL PRS (DL PRS#1) to the target UE 200. The second TRP 212 (TRP#2) can send a second DL PRS (DL PRS#2) to the target UE 200. The first UE 201 (UE#1) can send a first SL PRS (SL PRS#1) to the target UE 200. The second UE 202 (UE#2) can send a second SL PRS (SL PRS#2) to the target UE 200.

[0083] For example, the target UE 200 may use the first UE 201 (UE#1) and the second TRP 212 (TRP#2) as RSTD references for RSTD measurements. In this example, the target UE 200 may measure and report the following RSTD measurements to the LMF 220: RSTD from the first TRP 211 (TRP#1) and the first UE 201 (UE#1), RSTD from the second TRP 212 (TRP#2) and the first UE 201 (UE#1), RSTD from the second UE 202 (UE#2) and the first UE 201 (UE#1), RSTD from the first TRP 211 (TRP#1) and the second TRP 212 (TRP#2), and RSTD from the second UE 202 (UE#2) and the second TRP 212 (TRP#2). TRP#1 and TRP#2 may be in the same gNB, or in different gNBs.

[0084] For example, assume that the synchronization source of UE#1 is cell#1, and TRP#2 is located in cell#2. If the LMF knows the time synchronization information between cell#1 and cell#2, the LMF can modify the RSTD measurements so that they have a single reference timing.

[0085] In one example, the target UE may inform the LMF whether the reference is used only for RSTD measurement between DL PRS resources, or whether the reference is also used for RSTD measurement between DL PRS and SL PRS.

[0086] Also note that the target UE may report one or more anchor UEs as candidates for RSTD reference to the LMF, and the target UE may suggest a specific timestamp for the anchor UE to send the SL PRS.

[0087] When the target UE measures RSTD from the SL PRS sent by the anchor UE, the LMF may require the location of the anchor UE at a specific timestamp.

[0088] If the LMF already has prior knowledge about the location of the anchor UE, or the target UE provides the location information of the anchor UE to be used as a reference, the target UE does not need to take any further action to obtain the location information of the anchor UE. In this paper, we can consider two options. First, the LMF can instruct the anchor UE to perform UE-based positioning and report its location information. Second, the LMF can try to estimate the location of the anchor UE. For example, the LMF can try to estimate the location of the anchor UE based on RAT-independent technology or RAT-dependent technology using DL PRS and / or UL SRS.

[0089] Taking into account the mobility of the target UE, the LMF may instruct the anchor UE to measure the DL PRS and send the SL PRS within a specific (short) time. For this purpose, the LMF may configure the anchor UE with a threshold for the time difference between DL PRS reception and SL PRS transmission. In other words, the LMF may instruct the anchor UE on the measurement behavior: the anchor UE may measure the DL PRS and send the SL PRS within the configured time gap indicated by the threshold.

[0090] Figure 3 A signaling diagram according to an example embodiment is illustrated.

[0091] refer to Figure 3 In block 301, the LMF sends assistance data to the target UE, the assistance data including DL PRS resource configuration. The target UE may participate in a SL-TDOA positioning session with one or more anchor UEs. The LMF may also be referred to as a network element of the core network.

[0092] LMF can also provide reference information to the target UE through high-layer signaling, such as "dl-PRS-ReferenceInfo-r16" of the LTE Positioning Protocol (LPP). Based on the current LPP structure, LMF can provide cell ID, TRP ID, PRS resource set ID, and PRS resource ID.

[0093] Alternatively or additionally, the target UE and / or one or more anchor UEs may be configured with a secondary link positioning reference signal (SL PRS) by the gNB and / or LMF. The target UE and / or one or more anchor UEs may be configured with candidate time-frequency resources for sending and receiving secondary link positioning reference signals by the gNB and / or LMF.

[0094] In block 302, the target UE sends a capability report to the LMF. The capability report at least indicates whether the target UE supports secondary link positioning.

[0095] In block 303, the LMF sends an indication to the target UE to use one or more references based on one or more allowed synchronization sources and / or one or more not allowed synchronization sources for SL-TDOA.

[0096] In other words, the LMF may indicate one or more allowed synchronization sources for reference for RSTD measurement, and the anchor UE that is using the one or more allowed synchronization sources may be considered as a candidate for RSTD measurement.

[0097] Alternatively or additionally, the LMF may indicate one or more synchronization sources that are not allowed to be used for reference, and the anchor UEs that are using these synchronization sources may not be considered as candidates for RSTD measurement.

[0098] For example, the LMF may indicate that an anchor UE using a gNB as a synchronization source is allowed as a candidate for reference, but an anchor UE using a Global Navigation Satellite System (GNSS) as a synchronization source is not allowed as a candidate for reference.

[0099] The LMF may also indicate whether the target UE should use a single reference or multiple references for measuring RSTD.

[0100] In box 304, the target UE reports the identifiers of one or more anchor UEs to the LMF as candidates for reference for SL-TDOA. In other words, the target UE reports the identifiers of one or more candidate UEs to the LMF. One or more candidate UEs may be synchronized to one of the one or more allowed synchronization sources. One or more candidate UEs may not be synchronized to one or more synchronization sources that are not allowed. One or more candidate UEs may be anchor UEs (or supporting UEs or auxiliary UEs) used for SL positioning. In this document, one or more candidate UEs may also be referred to as one or more candidate user equipment.

[0101] In block 305, based on the identifiers of the one or more candidate UEs, the LMF sends a request for positioning measurement reporting to the one or more candidate UEs, and the LMF configures a threshold for the time difference between the timestamp of DL PRS reception and the timestamp of SLPRS transmission for the one or more candidate UEs. For example, the time difference may be defined as follows: (timestamp #1 received by DL PRS)-(timestamp #2 sent by SL PRS)<configured threshold. In other words, a given anchor UE may measure DL PRS and send SL PRS within the configured time gap indicated by the threshold.

[0102] In block 306, the gNB (or a TRP connected to the gNB) sends the DL PRS to the target UE and one or more candidate UEs. Alternatively, the target UE and one or more candidate UEs may receive the DL PRS from different gNBs or TRPs.

[0103] In block 307, one or more candidate UEs send the SL PRS to the target UE.

[0104] In block 308, based on the request for positioning measurement reporting, one or more candidate UEs measure and report to the LMF their DL positioning measurements based on the DL PRS received by the given anchor UE from the gNB (or TRP).

[0105] In block 309 , the target UE decides or selects at least one anchor UE from one or more candidate UEs as a reference for RSTD measurement.

[0106] In block 310, the target UE measures RSTD between at least two reference signals, wherein the at least two reference signals include at least a SL PRS received from at least one anchor UE selected as a reference. The at least two reference signals may also include at least one of the following: a DL PRS received from a network element of the radio access network (e.g., a gNB or a TRP), or a SL PRS received from another UE. In other words, the target UE may measure RSTD from a specific DL PRS resource and a SL PRS resource, or from two SL PRS resources from different anchor UEs.

[0107] In block 311, the target UE reports the measured RSTD and reference information of the measured RSTD to the LMF, for example via the LTE Positioning Protocol (LPP). The reference information includes at least one of the following: an identifier of at least one anchor UE selected as a reference, an identifier of a resource associated with a SL PRS sent from at least one anchor UE, synchronization source information of at least one anchor UE, and / or a timestamp of the SL PRS sent by at least one anchor UE. The target UE may also report the timestamp of the RSTD measurement. The measured RSTD and the reference information may be reported in the same report, or they may be reported separately.

[0108] The synchronization source information indicates at least one synchronization source used by at least one anchor UE. For example, the synchronization source information may indicate at least one of the following: an access node (such as a gNB), an NR cell ID (NCI), a physical cell identity, a physical cell identity and a synchronization signal block (SSB) identity, a physical cell identity and a transmission and reception point (TRP) identity, or a global navigation satellite system (GNSS).

[0109] The timestamp of the SL PRS received from the at least one anchor UE may indicate a reception time of the SL PRS at the target UE, or a transmission time of the SL PRS at the at least one anchor UE used as a reference.

[0110] The reference information may also include the location of at least one anchor UE at the timestamp (ie, the location at the time indicated by the timestamp), if the target UE knows the location.

[0111] If RSTD is measured between a DL PRS and a SL PRS, the report may indicate that the reference is valid for both DL PRS and SL PRS. If RSTD is measured between two SL PRSs, the report may indicate that the reference is valid for SL PRS.

[0112] In block 312, the LMF estimates the location of the target UE based on RSTD measurements collected from the target UE and / or DL ​​positioning measurements provided by at least one anchor UE.

[0113] If the target UE uses a single RSTD reference, the LMF can run the position estimation algorithm with the single reference.

[0114] If the UE uses multiple RSTD references, the LMF may need to run the position estimation algorithm multiple times with different references.

[0115] Figure 4 A signaling diagram according to an example embodiment is illustrated. In this example embodiment, the target UE may suggest a timestamp for the anchor UE to measure the DL PRS or send the SL PRS at a specific time in the future. Based on the suggestion from the target UE, the LMF may request the anchor UE to measure the DL PRS and / or send the SL PRS at a specific time in the future.

[0116] refer to Figure 4 In block 401, the LMF sends assistance data to the target UE, the assistance data including DL PRS resource configuration. The target UE may participate in a SL-TDOA positioning session with one or more anchor UEs. The LMF may also be referred to as a network element of the core network.

[0117] LMF can also provide reference information to the target UE through high-layer signaling, such as "dl-PRS-ReferenceInfo-r16" of the LTE Positioning Protocol (LPP). Based on the current LPP structure, LMF can provide cell ID, TRP ID, PRS resource set ID, and PRS resource ID.

[0118] Alternatively or additionally, the target UE and / or one or more anchor UEs may be configured with a secondary link positioning reference signal (SL PRS) by the gNB and / or LMF. The target UE and / or one or more anchor UEs may be configured with candidate time-frequency resources for sending and receiving secondary link positioning reference signals by the gNB and / or LMF.

[0119] In block 402, the target UE sends a capability report to the LMF. The capability report at least indicates whether the target UE supports secondary link positioning.

[0120] In block 403, the LMF sends an indication to the target UE to use one or more references included in the candidate UEs of one or more allowed synchronization sources for SL-TDOA.

[0121] In other words, the LMF may indicate one or more allowed synchronization sources for reference for RSTD measurement, wherein an anchor UE that is using the one or more allowed synchronization sources may be considered as a candidate for RSTD measurement.

[0122] Alternatively or additionally, the LMF may indicate one or more synchronization sources that are not allowed to be used for reference, wherein the anchor UE that is using these synchronization sources may not be considered as a candidate for RSTD measurement.

[0123] For example, the LMF may indicate that an anchor UE using a gNB as a synchronization source is allowed as a candidate for reference, but an anchor UE using a GNSS as a synchronization source is not allowed as a candidate for reference.

[0124] The LMF may also indicate whether the target UE should use a single reference or multiple references for measuring RSTD.

[0125] In box 404, the target UE reports the identifiers of one or more anchor UEs to the LMF as candidates for reference for SL-TDOA. In other words, the target UE reports the identifiers of one or more candidate UEs to the LMF. One or more candidate UEs may be synchronized to one of the one or more allowed synchronization sources. One or more candidate UEs may not be synchronized to one or more synchronization sources that are not allowed. One or more candidate UEs may be anchor UEs (or supporting UEs or auxiliary UEs) used for SL positioning. In this document, one or more candidate UEs may also be referred to as one or more candidate user equipment.

[0126] The target UE may also send one or more suggested future timestamps to the LMF for measuring DL PRS at one or more candidate UEs or sending SL PRS from one or more candidate UEs. Alternatively, the target UE may send one or more suggested future timestamps directly to one or more candidate UEs via a secondary link.

[0127] In block 405, based on the identifiers of one or more candidate UEs, the LMF sends a request for positioning measurement reporting to the one or more candidate UEs, and the LMF configures a threshold for the time difference between the timestamp of DL PRS reception and the timestamp of SLPRS transmission for the one or more candidate UEs. For example, the time difference may be defined as follows: (timestamp #1 of DL PRS reception)-(timestamp #2 of SL PRS transmission)<configured threshold. In other words, a given anchor UE may measure DL PRS and transmit SL PRS within the configured time gap.

[0128] The LMF may also provide one or more specific timestamps to one or more candidate UEs for measuring the DL PRS or sending the SL PRS at the timestamps. The one or more specific timestamps may be based on one or more suggested future timestamps provided by the target UE. For example, the LMF may request one or more candidate UEs to measure the DL PRS or send the SL PRS at one or more suggested future timestamps.

[0129] In block 406, the gNB (or a TRP connected to the gNB) sends the DL PRS to the target UE and one or more candidate UEs. Alternatively, the target UE and one or more candidate UEs may receive the DL PRS from different gNBs or TRPs.

[0130] In block 407, one or more candidate UEs send the SL PRS to the target UE. The one or more candidate UEs may measure the DL PRS or send the SL PRS at a time indicated by at least one of the one or more timestamps requested by the LMF (or suggested by the target UE).

[0131] In block 408, based on the request for positioning measurement reporting, one or more candidate UEs measure and report to the LMF their DL positioning measurements based on the DL PRS received by the given anchor UE from the gNB (or TRP).

[0132] In block 409, the target UE decides or selects at least one anchor UE from one or more candidate UEs as a reference for RSTD measurement.

[0133] In block 410, the target UE measures RSTD between at least two reference signals, wherein the at least two reference signals include at least one SL PRS received from at least one anchor UE selected as a reference. The at least two reference signals may also include at least one of the following: a DL PRS received from a network element of the radio access network (e.g., a gNB or a TRP), or a SL PRS received from another UE. In other words, the target UE may measure RSTD from a specific DL PRS resource and a SL PRS resource, or from two SL PRS resources from different anchor UEs.

[0134] In block 411, the target UE reports the measured RSTD and reference information of the measured RSTD to the LMF, for example, via LPP. The reference information includes at least one of the following: an identifier of at least one anchor UE selected as a reference, an identifier of a resource associated with a SL PRS sent from at least one anchor UE, synchronization source information of at least one anchor UE, and / or a timestamp of the SL PRS sent by at least one anchor UE. The target UE may also report the timestamp of the RSTD measurement. The measured RSTD and the reference information may be reported in the same report, or they may be reported separately.

[0135] The synchronization source information indicates at least one synchronization source used by at least one anchor UE. For example, the synchronization source information may indicate at least one of: an access node (such as a gNB), an NR cell ID (NCI), a physical cell identity, a physical cell identity and an SSB identity, a physical cell identity and a TRP identity, or a GNSS.

[0136] The timestamp of the SL PRS received from the at least one anchor UE may indicate a reception time of the SL PRS at the target UE, or a transmission time of the SL PRS at the at least one anchor UE used as a reference.

[0137] The reference information may also include the location of at least one anchor UE at the timestamp (ie, the location at the time indicated by the timestamp), if the target UE knows the location.

[0138] If RSTD is measured between a DL PRS and a SL PRS, the report may indicate that the reference is valid for both DL PRS and SL PRS. If RSTD is measured between two SL PRSs, the report may indicate that the reference is valid for SL PRS.

[0139] In block 412, the LMF estimates the location of the target UE based on RSTD measurements collected from the target UE and / or DL ​​positioning measurements provided by at least one anchor UE.

[0140] If the target UE uses a single RSTD reference, the LMF can run the position estimation algorithm using the single reference.

[0141] If the UE uses multiple RSTD references, the LMF may need to run the position estimation algorithm multiple times using different references.

[0142] Figure 5 A signaling diagram according to an example embodiment is illustrated. In this example embodiment, the LMF requests the anchor UE to report its own location, which is done at a specific timing according to UE-based positioning using RAT-dependent or RAT-independent techniques.

[0143] refer to Figure 5 In block 501, the LMF sends assistance data to the target UE, the assistance data including DL PRS resource configuration. The target UE may participate in a SL-TDOA positioning session with one or more anchor UEs. The LMF may also be referred to as a network element of the core network.

[0144] LMF can also provide reference information to the target UE through high-layer signaling, such as "dl-PRS-ReferenceInfo-r16" of the LTE Positioning Protocol (LPP). Based on the current LPP structure, LMF can provide cell ID, TRP ID, PRS resource set ID, and PRS resource ID.

[0145] Alternatively or additionally, the target UE and / or one or more anchor UEs may be configured with a secondary link positioning reference signal (SL PRS) by the gNB and / or LMF. The target UE and / or one or more anchor UEs may be configured with candidate time-frequency resources for sending and receiving secondary link positioning reference signals by the gNB and / or LMF.

[0146] In block 502, the target UE sends a capability report to the LMF. The capability report at least indicates whether the target UE supports secondary link positioning.

[0147] In block 503, the LMF sends an indication to the target UE to use one or more references included in the candidate UEs of one or more allowed synchronization sources for SL-TDOA.

[0148] In other words, the LMF may indicate one or more allowed synchronization sources for reference for RSTD measurement, wherein an anchor UE that is using the one or more allowed synchronization sources may be considered as a candidate for RSTD measurement.

[0149] Alternatively or additionally, the LMF may indicate one or more synchronization sources that are not allowed to be used for reference, wherein the anchor UE that is using these synchronization sources may not be considered as a candidate for RSTD measurement.

[0150] For example, the LMF may indicate that an anchor UE using a gNB as a synchronization source is allowed as a candidate for reference, but an anchor UE using a GNSS as a synchronization source is not allowed as a candidate for reference.

[0151] The LMF may also indicate whether the target UE should use a single reference or multiple references for measuring RSTD.

[0152] In box 504, the target UE reports the identifiers of one or more anchor UEs to the LMF as candidates for reference for SL-TDOA. In other words, the target UE reports the identifiers of one or more candidate UEs to the LMF. One or more candidate UEs may be synchronized to one of the one or more allowed synchronization sources. One or more candidate UEs may not be synchronized to one or more synchronization sources that are not allowed. One or more candidate UEs may be anchor UEs (or supporting UEs or auxiliary UEs) used for SL positioning. In this document, one or more candidate UEs may also be referred to as one or more candidate user equipment.

[0153] In block 505, based on the identifiers of the one or more candidate UEs, the LMF sends a request to the one or more candidate UEs to measure the DL PRS at one or more specific time stamps and report corresponding location information of the one or more candidate UEs to the LMF.

[0154] In block 506, the LMF sends a request to the target UE to report RSTD measurements obtained at one or more specific timestamps. The one or more specific timestamps indicated to the target UE may be the same as the one or more specific timestamps indicated to the one or more candidate UEs.

[0155] In block 507, the gNB (or a TRP connected to the gNB) sends the DL PRS to the target UE and one or more candidate UEs. Alternatively, the target UE and one or more candidate UEs may receive the DL PRS from different gNBs or TRPs.

[0156] In block 508, one or more candidate UEs send the SL PRS to the target UE.

[0157] In block 509, based on the request to report location information, one or more candidate UEs report their location information and corresponding timestamps to the LMF. The location information indicates the location of a given candidate UE at a corresponding timestamp.

[0158] In block 510, the target UE decides or selects at least one anchor UE from one or more candidate UEs as a reference for RSTD measurement.

[0159] In box 511, the target UE measures the RSTD between at least two reference signals, wherein the at least two reference signals include at least one SL PRS received from at least one anchor UE selected as a reference. The at least two reference signals may also include at least one of the following: a DL PRS received from a network element of the radio access network (e.g., a gNB or a TRP), or a SL PRS received from another UE. In other words, the target UE may measure RSTD from a specific DL PRS resource and a SL PRS resource, or measure RSTD from two SL PRS resources from different anchor UEs. The measurement is performed at one or more specific timestamps indicated by the LMF.

[0160] In block 512, the target UE reports the measured RSTD and reference information of the measured RSTD to the LMF, for example, via LPP. The reference information includes at least one of the following: an identifier of at least one anchor UE selected as a reference, an identifier of a resource associated with a SL PRS sent from at least one anchor UE, synchronization source information of at least one anchor UE, and / or a timestamp of the SL PRS sent by at least one anchor UE. The target UE may also report a timestamp of the RSTD measurement. The measured RSTD and the reference information may be reported in the same report, or they may be reported separately.

[0161] The synchronization source information indicates at least one synchronization source used by at least one anchor UE. For example, the synchronization source information may indicate at least one of: an access node (such as a gNB), an NR cell ID (NCI), a physical cell identity, a physical cell identity and an SSB identity, a physical cell identity and a TRP identity, or a GNSS.

[0162] The timestamp of the SL PRS received from the at least one anchor UE may indicate a reception time of the SL PRS at the target UE, or a transmission time of the SL PRS at the at least one anchor UE used as a reference.

[0163] If RSTD is measured between a DL PRS and a SL PRS, the report may indicate that the reference is valid for both DL PRS and SL PRS. If RSTD is measured between two SL PRSs, the report may indicate that the reference is valid for SL PRS.

[0164] In block 513, the LMF estimates the location of the target UE based on RSTD measurements collected from the target UE and / or location information provided by at least one anchor UE.

[0165] If the target UE uses a single RSTD reference, the LMF can run the position estimation algorithm using the single reference.

[0166] If the UE uses multiple RSTD references, the LMF may need to run the position estimation algorithm multiple times using different references.

[0167] Figure 6 A flow chart according to an example embodiment of a method performed by an apparatus such as a user equipment in a radio access network or comprising a user equipment in a radio access network or included in a user equipment in a radio access network is illustrated. The 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 Figure 1 A user device 100 is provided.

[0168] See also Figure 6 , in block 601, at least one user equipment is selected from one or more candidate user equipments as a reference for reference signal time difference (RSTD) measurement.

[0169] In block 602, RSTD is measured between at least two reference signals, wherein the at least two reference signals include at least one secondary link positioning reference signal (SLPRS) received from at least one user equipment selected as a reference. For example, the at least two reference signals may also include at least one of the following: a downlink positioning reference signal received from a network element of a radio access network, or a secondary link reference signal received from another user equipment.

[0170] In box 603, a report is sent to a network element of the core network (e.g., LMF), wherein the report includes at least one of: an identifier of at least one user device selected as a reference for RTSD measurement, an identifier of a resource associated with a secondary link positioning reference signal received from at least one user device, synchronization source information indicating at least one synchronization source of at least one user device, or a timestamp of the secondary link positioning reference signal received from at least one user device.

[0171] The apparatus may further send a measurement report to a network element of the core network, the measurement report indicating the measured RSTD associated with at least one user equipment selected as a reference for RTSD measurement.The measurement report may be sent together with the above-mentioned report or separately therefrom.

[0172] Figure 7 A flow chart according to an example embodiment of a method performed by an apparatus such as a network element of a core network or a network element comprising a core network or a network element included in a core network is illustrated. The network element may correspond to Figure 1 LMF 112.

[0173] refer to Figure 7 , in block 701, receiving a report from a target user equipment, wherein the report includes at least one of: an identifier of at least one user equipment selected as a reference for measuring a reference signal time difference (RSTD), an identifier of a resource associated with a secondary link positioning reference signal (SL PRS) used to measure RSTD, synchronization source information indicating at least one synchronization source of at least one user equipment selected as a reference for measuring RSTD, or a timestamp of the secondary link positioning reference signal used to measure RSTD; and

[0174] In block 702, a location of a target user equipment is estimated based at least in part on the report.

[0175] The apparatus may further receive a measurement report from the target user equipment, the measurement report indicating a measured RSTD associated with at least one user equipment selected as a reference for RTSD measurement, wherein the location of the target user equipment may be estimated based at least in part on the measured RSTD. The measurement report may be received together with the above-mentioned report or separately therefrom.

[0176] Figure 8 A flow chart according to an example embodiment of a method performed by an apparatus such as a user equipment in a radio access network or comprising a user equipment in a radio access network or included in a user equipment in a radio access network is illustrated. The 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), an anchor UE, or an anchor user equipment. The user equipment may correspond to Figure 1 of user equipment 102.

[0177] refer to Figure 8 In block 801, a threshold is received from a network element (eg, LMF) of a core network, wherein the threshold is a time difference between receiving a downlink positioning reference signal (DL PRS) and sending a sidelink positioning reference signal (SL PRS).

[0178] In block 802, a secondary link positioning reference signal is sent to a target user equipment based at least on the threshold, wherein a time difference between receiving the downlink positioning reference signal and sending the secondary link positioning reference signal is less than the threshold.

[0179] The above is based on Figure 3-8The described boxes, related functions, and information exchanges (messages) are not in absolute time order, and some of them may be performed simultaneously, or may be performed in an order different from the described order. Other functions may also be performed between or within them, and other information may be sent, and / or other rules may be applied. Some boxes or parts of boxes or one or more pieces of information may also be omitted, or replaced with corresponding boxes or parts of boxes or one or more pieces of information.

[0180] As used herein, “at least one of: <a list of two or more units / elements>” and “at least one of <a list of two or more units / elements>” and similar expressions (wherein a list of two or more units / elements is connected by “and” or “or”) mean at least any one of the units / elements, or at least any two or more of the units / elements, or at least all of the units / elements.

[0181] In some example embodiments, the network may indicate to the UE that a DL PRS resource may be used as a reference for DL ​​RSTD, DL PRS-RSRP, and UE Rx-Tx time difference measurements in the higher layer parameter nr-DL-PRS-ReferenceInfo. The reference indicated by the network to the UE may also be used by the UE to determine how to apply the higher layer parameters nr-DL-PRS-ExpectedRSTD and nr-DL-PRS-ExpectedRSTD-Uncertainty. The UE expects the reference to be indicated at any time when a DL PRS is expected to be received. This reference provided by nr-DL-PRS-ReferenceInfo may include a dl-PRS-ID, a DL PRS resource set ID, and optionally a single DL PRS resource ID or a list of DL PRS resource IDs. As long as the condition that the DL PRS resource used belongs to a single DL PRS resource set is met, the UE may use different DL PRS resources or different DL PRS resource sets to determine the reference for RSTD measurement. If the UE chooses to use a different reference than indicated by the network, it is expected to report the dl-PRS-ID, DL PRS resource ID, or DL ​​PRS resource set ID used to determine the reference. For the reported reference, the UE can report whether this reference is valid only for DL ​​PRS, or whether it is also valid for DL ​​PRS and SL PRS for RSTD measurement. If the UE chooses to use a different reference than indicated by the network, it is expected to report the UEID, SL PRS resource ID, the UE's synchronization source information, and the timestamp of the SL PRS resource ID sent. If the reference information for RSTD measurement from the SL PRS resources and DL PRS resources is not included in the report, the network may prioritize nr-DL-PRS-ReferenceInfo to assume the reference for RSTD measurement. The network may indicate to the UE to use a single RSTD reference from the SL PRS resources with a specific synchronization source, and the UE may be expected to report the RSTD reference used.

[0182] As an additional consideration, although the UE reports an RSTD reference, the reported RSTD reference may not be the reference used for the reported RSTD measurement. For example, the UE may report TRP#1 and UE#1 as the reference for the RSTD measurement. If the network allows the UE to report RSTD from TRP#2 and UE#2, there may be rules for the LMF to assume what the reference used for the reported RSTD measurement is. In this case, one option is for the LMF to assume the DL PRS instead of the SL PRS as the RSTD reference.

[0183] In some example embodiments, if the LMF does not have proper knowledge of the anchor UE, the LMF may only configure the current reference configuration (reference configuration for DL-PRS). However, the target UE may still use the SL-UE as the SL-TDoA reference, and the target UE may replace the configured current reference with the SL-UE / SL-PRS for SL-TDOA.

[0184] The target UE may be allowed to use multiple references and report them. For example, if the LMF supports running a separate position estimation algorithm such as least squares (LS) for a given reference, it may allow the use of multiple RSTD references. In turn, the target UE can report RSTD measurements more flexibly. For example, the UE may select one TRP and one anchor UE as references, or it may select two different anchor UEs as references. In addition, even if the target UE selects two references, the LMF may perform further calculations to efficiently use a single reference. Even if the UE reports a specific TRP as the DL-TDOA reference and it reports the SL-UE as the SL-TDOA reference, the TRP is located in the gNB and the SL-UE may be synchronized to the same gNB.

[0185] Fig. 9 An example of an apparatus 900 in a radio access network is shown, the apparatus comprising a method for performing Figure 6 methods, Figure 8 For example, the apparatus 900 may be an apparatus such as a user device or including a user device or included in a user device. The user device may correspond to Figure 1 The user equipment 100, 102 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), an anchor UE, a target UE, or a target user equipment.

[0186] The apparatus 900 includes at least one processor 910. The at least one processor 910 interprets computer program instructions and processes data. The at least one processor 910 may include one or more programmable processors. The at least one processor 910 may include programmable hardware with embedded firmware, and may alternatively or additionally include one or more application specific integrated circuits (ASICs).

[0187] At least one processor 910 is coupled to at least one memory 920. The at least one processor is configured to read data from at least one memory 920 and write data to at least one memory 920. At least one memory 920 may include one or more memory cells. The memory cell 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, there may be one or more non-volatile memory cells, or alternatively, there may be one or more volatile memory cells. Volatile memory may be, for example, a random access memory (RAM), a dynamic random access memory (DRAM), or a synchronous dynamic random access memory (SDRAM). Non-volatile memory may be, for example, a read-only memory (ROM), a programmable read-only memory (PROM), an electrically erasable programmable read-only memory (EEPROM), a flash memory, an optical memory, or a magnetic memory. In general, a memory may be referred to as a non-transitory computer-readable medium. As used herein, the term "non-transitory" is a restriction on the medium itself (i.e., tangible, not a signal), rather than a restriction on data storage persistence (e.g., RAM versus ROM). At least one memory 920 stores computer readable instructions, which are executed by at least one processor 910 to perform one or more example embodiments described above. For example, non-volatile memory stores computer readable instructions, and at least one processor 910 executes instructions using volatile memory for temporary storage of data and / or instructions. Computer readable instructions may refer to computer program code.

[0188] The computer readable instructions may have been pre-stored in at least one memory 920, 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). At least one processor 910 executes the computer readable instructions so that the device 900 performs 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 execution of any of the above-described methods and / or blocks.

[0189] 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, apparatus or device (such as a computer). As used herein, the term "non-transitory" is a limitation on the medium itself (i.e., tangible, not a signal), not on the persistence of data storage (e.g., RAM versus ROM).

[0190] The device 900 may also include or be connected to an input unit 930. The input unit 930 may include one or more interfaces for receiving user input. For example, the one or more interfaces may include 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 930 may include an interface to which an external device may be connected.

[0191] The device 900 may also include an output unit 940. The output unit may include or be connected to one or more displays capable of rendering visual content, such as a light emitting diode (LED) display, a liquid crystal display (LCD), and / or a liquid crystal on silicon (LCoS) display. The output unit 940 may also include one or more audio outputs. The one or more audio outputs may be, for example, a speaker.

[0192] The device 900 also includes a connection unit 950. The connection unit 950 enables wireless connection with one or more external devices. The connection unit 950 includes at least one transmitter and at least one receiver that can be integrated into the device 900 or the device 900 can be connected to. At least one transmitter includes at least one transmit antenna, and at least one receiver includes at least one receive antenna. The connection unit 950 may include an integrated circuit or a group of integrated circuits that provide wireless communication capabilities for the device 900. Alternatively, the wireless connection can be a hardwired application-specific integrated circuit (ASIC). The connection unit 950 may include one or more components controlled by a corresponding control unit, 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.

[0193] It should be noted that the apparatus 900 may also include Fig. 9 The various components not shown in the figure. The various components can be hardware components and / or software components.

[0194] Fig.10 An example of an apparatus 1000 in a core network is shown, the apparatus comprising a device for performing Figure 7 For example, the apparatus 1000 may be an apparatus such as a network element of a core network or a network element including a core network or included in a network element of a core network. The network element may correspond to Figure 1 The LMF 112. A network element may also be referred to as a network node or a location server, for example.

[0195] The device 1000 may, for example, include a circuit or chipset suitable for implementing one or more of the example embodiments described above. The device 1000 may be an electronic device including one or more electronic circuits. The device 1000 may include a communication control circuit 1010 (such as at least one processor) and at least one memory 1020 storing instructions, which, when executed by at least one processor, causes the device 1000 to perform one or more of the example embodiments described above. Such instructions may, for example, include computer program code (software) 1022, wherein at least one memory and computer program code (software) 1022 are configured together with at least one processor to cause the device 1000 to perform one or more of the example embodiments described above. In this document, computer program code may in turn refer to instructions, which, when executed by at least one processor, causes the device 1000 to perform one or more of the example embodiments described above. That is, at least one processor and at least one memory storing instructions may provide a means for providing or causing the execution of any of the methods and / or blocks described above.

[0196] The processor is coupled to the memory 1020. The processor is configured to read data from the memory 1020 and write data to the memory 1020. The memory 1020 may include one or more memory cells. The memory cell 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, there may be one or more non-volatile memory cells, or alternatively, there may be one or more volatile memory cells. Volatile memory may be, for example, a random access memory (RAM), a dynamic random access memory (DRAM), or a synchronous dynamic random access memory (SDRAM). Non-volatile memory may be, for example, a read-only memory (ROM), a programmable read-only memory (PROM), an electrically erasable programmable read-only memory (EEPROM), a flash memory, an optical memory, or a magnetic memory. In general, memory may be referred to as a non-temporary computer-readable medium. As used herein, the term "non-temporary" is a restriction on the medium itself (i.e., tangible, not a signal), rather than a restriction on data storage persistence (e.g., RAM versus ROM). The memory 1020 stores computer readable instructions executed by the processor. For example, non-volatile memory stores computer readable instructions, and the processor executes the instructions using volatile memory for temporary storage of data and / or instructions.

[0197] The computer readable instructions may have been pre-stored in the memory 1020, alternatively or additionally, they may be received by the device via an electromagnetic carrier signal and / or may be copied from a physical entity (e.g., a computer program product). The execution of the computer readable instructions causes the device 1000 to perform one or more functions described above.

[0198] The memory 1020 may be implemented using any suitable data storage technology, such as semiconductor-based memory devices, flash memory, magnetic memory devices and systems, optical memory 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 current neighbor cell list, and in some example embodiments, may store the structure of frames used in detected neighbor cells.

[0199] The device 1000 may also include a communication interface 1030, which includes hardware and / or software for implementing a communication connection according to one or more communication protocols. The communication interface 1030 includes at least one transmitter (Tx) and at least one receiver (Rx) that can be integrated into the device 1000 or the device 1000 can be connected to. The communication interface 1030 may include one or more components controlled by a corresponding control unit, 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.

[0200] The communication interface 1030 provides the device with radio communication capabilities to communicate in a cellular communication system. The communication interface may, for example, provide a radio interface to one or more user equipments. The device 1000 may also include another interface toward a core network (such as a network coordinator device or AMF) and / or to an access node of a cellular communication system.

[0201] It should be noted that the apparatus 1000 may also include Fig.10 The various components not shown in the figure. The various components can be hardware components and / or software components.

[0202] As used in this application, the term "circuitry" may refer to one or more or all of the following: a) a hardware circuit implementation only (such as an implementation in analog and / or digital circuits only), and b) a combination of hardware circuitry and software, such as (as applicable): i) a combination of analog and / or digital hardware circuitry with software / firmware, and ii) any portion of a hardware processor (including a digital signal processor) with software, software, and memory that work together to enable a device (such as a mobile phone) to perform various functions; and c) hardware circuitry and / or processors (such as a microprocessor or a portion of a microprocessor) that require software (e.g., firmware) to operate, but that software may not be present when it is not required for operation.

[0203] This definition of "circuitry" applies to all uses of the 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 only a hardware circuit or processor (or multiple processors) or a portion of a hardware circuit or processor and its accompanying software and / or firmware. For example, and if applicable to a particular claim element, the term "circuitry" also covers a baseband integrated circuit or processor integrated circuit for a mobile device, or a similar integrated circuit in a server, cellular network device, or other computing or network device.

[0204] The techniques and methods described herein can be implemented by various means. 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 example embodiment 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, the implementation can be implemented by a module of at least one chipset that performs the functions (e.g., processes, functions, etc.) described herein. The software code can be stored in a storage unit and executed by a processor. The storage unit can be implemented in a processor or outside a processor. In the latter case, as known in the art, it can be communicatively coupled to the processor via various means. In addition, it will be understood by those skilled in the art that the components of the system described herein can be rearranged and / or supplemented by additional components to facilitate the implementation of various aspects of its description, etc., and they are not limited to the precise configurations set forth in the given figures.

[0205] It is obvious to those skilled in the art that, as technology advances, the inventive concept can be implemented in various ways. The embodiments are not limited to the above-described example embodiments, but may vary within the scope of the claims. Therefore, all words and expressions should be interpreted broadly, and they are intended to illustrate rather than limit the example embodiments.

Claims

1. An apparatus in a radio access network, the apparatus comprising at least one processor and at least one memory storing instructions, the instructions, when executed by the at least one processor, causing the apparatus to at least: Selecting at least one user equipment from one or more candidate user equipments as a reference for reference signal time difference (RSTD) measurement; The RSTD between at least two reference signals is measured, where The at least two reference signals include at least a secondary link positioning reference signal received from the at least one user equipment selected as the reference; as well as Sending a report to a network element of a core network, the report comprising at least one of: an identifier of the at least one user device selected as the reference for the RTSD measurement, an identifier of a resource associated with the sidelink positioning reference signal received from the at least one user device, synchronization source information indicating at least one synchronization source of the at least one user device, or a timestamp of the sidelink positioning reference signal received from the at least one user device.

2. The device according to claim 1, further comprising: A measurement report is sent to the network element of the core network, the measurement report indicating the measured RSTD associated with the at least one user equipment selected as the reference for the RTSD measurement.

3. A device according to any one of the preceding claims, wherein: The at least two reference signals further include at least one of: a downlink positioning reference signal received from a network element of the radio access network, or a secondary link reference signal received from another user equipment.

4. The device according to claim 3, wherein: The report indicates that the reference is used to measure RSTD between the downlink positioning reference signal and the secondary link positioning reference signal received from the at least one user equipment selected as the reference.

5. A device according to any one of the preceding claims, wherein: The synchronization source information indicates at least one of the following: an access node, a cell identifier, a physical cell identifier, the physical cell identifier and a synchronization signal block identifier, the physical cell identifier and a sending and receiving point identifier, or a global navigation satellite system.

6. A device according to any one of the preceding claims, wherein: The timestamp of the secondary link positioning reference signal received from the at least one user equipment indicates a reception time of the secondary link positioning reference signal at the apparatus, or a transmission time of the secondary link positioning reference signal at the at least one user equipment.

7. A device according to any one of the preceding claims, wherein: The report further comprises a location of the at least one user equipment at the timestamp, wherein the at least one user equipment is selected as the reference.

8. The device according to any one of the preceding claims, further comprising: receiving, from said network element of said core network, an indication indicating one or more allowed synchronization sources for said reference, in, The one or more candidate user equipment are synchronized to at least one allowed synchronization source of the one or more allowed synchronization sources.

9. The device according to any one of the preceding claims, further comprising: receiving an indication from a network element of the core network indicating one or more synchronization sources that are not allowed to be used for the reference, in, The one or more candidate user equipment are not synchronized to the disallowed one or more synchronization sources.

10. The device according to any one of the preceding claims, further comprising: One or more suggested timestamps for measuring a downlink positioning reference signal at the at least one user equipment or for sending the downlink positioning reference signal from the at least one user equipment are sent to the at least one user equipment or the network element of the core network.

11. The device according to any one of the preceding claims, further comprising: The identifiers of the one or more candidate user equipments are reported to the network element of the core network.

12. The device according to any one of the preceding claims, further comprising: receiving an indication from the network element of the core network to measure the RSTD using a single reference, in, The at least one user equipment is selected based at least in part on the indication using the single reference, the at least one user equipment comprising a single user equipment.

13. The device according to any one of claims 1 to 11, further comprising: receiving an indication from the network element of the core network to measure the RSTD using a plurality of references, in, The at least one user equipment is selected based at least in part on the indication using the plurality of references.

14. An apparatus in a core network, the apparatus comprising at least one processor and at least one memory storing instructions, the instructions, when executed by the at least one processor, causing the apparatus to at least: receiving a report from a target user equipment, the report comprising at least one of: an identifier of at least one user equipment selected as a reference for measuring a reference signal time difference RSTD, an identifier of a resource associated with a secondary link positioning reference signal used to measure the RSTD, synchronization source information indicating at least one synchronization source of the at least one user equipment selected as the reference for measuring the RSTD, or a timestamp of the secondary link positioning reference signal used to measure the RSTD; and Based at least in part on the report, a location of the target user equipment is estimated.

15. The device according to claim 14, further comprising: receiving a measurement report from the target user equipment, the measurement report indicating the measured RSTD associated with the at least one user equipment selected as the reference for the RTSD measurement, wherein, The location of the target user equipment is estimated based at least in part on the measured RSTD.

16. The device according to any one of claims 14-15, wherein: The report indicates that the reference is used to measure RSTD between a downlink positioning reference signal and the secondary link positioning reference signal.

17. The device according to any one of claims 14 to 16, wherein: The synchronization source information indicates at least one of the following: an access node, a cell identifier, a physical cell identifier, the physical cell identifier and a synchronization signal block identifier, the physical cell identifier and a sending and receiving point identifier, or a global navigation satellite system.

18. The device according to any one of claims 14 to 17, wherein: The timestamp of the secondary link positioning reference signal indicates a reception time of the secondary link positioning reference signal at the target user equipment, or a transmission time of the secondary link positioning reference signal at the at least one user equipment.

19. The device according to any one of claims 14 to 18, wherein: The report further comprises a location of the at least one user equipment at the timestamp, wherein the at least one user equipment is selected as the reference for measuring the RSTD.

20. The device according to any one of claims 14 to 19, further comprising: An indication is sent to the target user equipment indicating one or more allowed synchronization sources for the reference.

21. The device according to any one of claims 14 to 20, further comprising: An indication is sent to the target user equipment indicating one or more synchronization sources that are not allowed to be used for the reference.

22. The device according to any one of claims 14 to 21, further comprising: receiving identifiers of one or more candidate user equipments for the reference from the target user equipment, wherein: The one or more candidate user equipments include at least the at least one user equipment.

23. The device according to claim 22, further comprising: Based on the identifiers of the one or more candidate user equipments, a threshold for a time difference between receiving a downlink positioning reference signal and sending the downlink positioning reference signal is sent to the one or more candidate user equipments.

24. The device according to any one of claims 22-23, further comprising: receiving from the target user equipment one or more suggested timestamps for measuring a downlink positioning reference signal at the one or more candidate user equipments or for transmitting the downlink positioning reference signal from the one or more candidate user equipments; and A request is sent to the one or more candidate user equipments to measure the downlink positioning reference signal or send the secondary link positioning reference signal at the one or more suggested time stamps.

25. The device according to any one of claims 22 to 24, further comprising: sending a request to the one or more candidate user equipments for reporting locations and corresponding timestamps of the one or more candidate user equipments; and receiving, based on the request, a report from the one or more candidate user equipment, the report indicating the location and the corresponding timestamp of the one or more candidate user equipment, in, The location of the target user equipment is estimated based at least in part on the location of the at least one user equipment included in the one or more candidate user equipments.

26. The device according to any one of claims 14 to 25, further comprising: sending an instruction to the target user equipment to measure the RSTD using a single reference, wherein: The at least one user equipment comprises a single user equipment.

27. The device according to any one of claims 14 to 25, further comprising: An instruction to use a plurality of references to measure the RSTD is sent to the target user equipment.

28. An apparatus in a radio access network, the apparatus comprising at least one processor and at least one memory storing instructions, the instructions when executed by the at least one processor causing the apparatus to at least: receiving, from a network element of the core network, a threshold value for a time difference between receiving a downlink positioning reference signal and sending a secondary link positioning reference signal; and Based at least on the threshold, the secondary link positioning reference signal is sent to the target user equipment, wherein: The time difference between receiving the downlink positioning reference signal and sending the secondary link positioning reference signal is less than the threshold.

29. The device according to claim 28, further causing the device to: receiving, from the target user equipment or from the network element of the core network, one or more suggested timestamps for measuring the downlink positioning reference signal or sending the secondary link positioning reference signal; and The downlink positioning reference signal is measured or the secondary link positioning reference signal is sent at a time indicated by at least one suggested timestamp of the one or more suggested timestamps.

30. A method comprising: selecting, by a device in a radio access network, at least one user equipment from one or more candidate user equipments as a reference for reference signal time difference (RSTD) measurement; Measuring, by the apparatus, RSTD between at least two reference signals, wherein the at least two reference signals include at least a secondary link positioning reference signal received from the at least one user equipment selected as the reference; as well as A report is sent by the device to a network unit of the core network, the report including at least one of the following: an identifier of the at least one user device selected as the reference for the RTSD measurement, an identifier of a resource associated with the secondary link positioning reference signal received from the at least one user device, synchronization source information indicating at least one synchronization source of the at least one user device, or a timestamp of the secondary link positioning reference signal received from the at least one user device.

31. A method comprising: Receiving, by a device in a core network, a report from a target user equipment, the report comprising at least one of the following: an identifier of at least one user equipment selected as a reference for measuring a reference signal time difference RSTD, an identifier of a resource associated with a secondary link positioning reference signal used to measure the RSTD, synchronization source information indicating at least one synchronization source of the at least one user equipment selected as the reference for measuring the RSTD, or a timestamp of the secondary link positioning reference signal used to measure the RSTD; as well as A location of the target user equipment is estimated, by the apparatus, based at least in part on the report.

32. A method comprising: receiving, by a device in the radio access network from a network element of the core network, a threshold value for a time difference between receiving a downlink positioning reference signal and sending a secondary link positioning reference signal; as well as The apparatus sends the secondary link positioning reference signal to a target user equipment based at least on the threshold, wherein the time difference between receiving the downlink positioning reference signal and sending the secondary link positioning reference signal is less than the threshold.

33. A non-transitory computer-readable medium comprising program instructions, which when executed by a device in a radio access network causes the device to perform at least the following operations: Selecting at least one user equipment from one or more candidate user equipments as a reference for reference signal time difference (RSTD) measurement; The RSTD between at least two reference signals is measured, where The at least two reference signals include at least a secondary link positioning reference signal received from the at least one user equipment selected as the reference; as well as Sending a report to a network element of a core network, the report comprising at least one of: an identifier of the at least one user device selected as the reference for the RTSD measurement, an identifier of a resource associated with the sidelink positioning reference signal received from the at least one user device, synchronization source information indicating at least one synchronization source of the at least one user device, or a timestamp of the sidelink positioning reference signal received from the at least one user device.

34. A non-transitory computer-readable medium comprising program instructions that, when executed by a device in a core network, cause the device to at least perform the following operations: receiving a report from a target user equipment, the report comprising at least one of: an identifier of at least one user equipment selected as a reference for measuring a reference signal time difference RSTD, an identifier of a resource associated with a secondary link positioning reference signal used to measure the RSTD, synchronization source information indicating at least one synchronization source of the at least one user equipment selected as the reference for measuring the RSTD, or a timestamp of the secondary link positioning reference signal used to measure the RSTD; and Based at least in part on the report, a location of the target user equipment is estimated.

35. A non-transitory computer-readable medium comprising program instructions that, when executed by a device in a radio access network, cause the device to at least: receiving, from a network element of the core network, a threshold value for a time difference between receiving a downlink positioning reference signal and sending a secondary link positioning reference signal; and Based at least on the threshold, the secondary link positioning reference signal is sent to the target user equipment, wherein: The time difference between receiving the downlink positioning reference signal and sending the secondary link positioning reference signal is less than the threshold.

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