Sidelink positioning reference signal configuration

Abstract

A method is disclosed, the method comprising: transmitting a message comprising a first reference signal and a first set of masks to one or more user equipments; receiving, from the one or more user equipments, at least one of: first mask channel information for each mask in the first set of masks, or a preferred sidelink positioning reference signal configuration based on the first mask channel information; and determining a first sidelink positioning reference signal configuration based at least in part on the first mask channel information or the preferred sidelink positioning reference signal configuration.

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. There are challenges in how to select an appropriate positioning reference signal configuration to provide high positioning accuracy and low latency. Summary of the invention

[0003] The scope of protection sought by the various example embodiments is set out in the claims. Example embodiments and features described in this specification that do not fall within the scope of the independent claims, if any, should be interpreted as useful examples for understanding the various embodiments.

[0004] According to one aspect, a device is provided, which includes at least one processor and at least one memory, wherein the at least one memory stores instructions, which when executed by the at least one processor causes the device to at least: transmit a message including a first reference signal and a first group of masks to one or more user devices; receive at least one of the following from one or more user devices: first mask channel information of each mask in the first group of masks, or a preferred side link positioning reference signal configuration based on the first mask channel information; and determine a first side link positioning reference signal configuration based at least in part on the first mask channel information or the preferred side link positioning reference signal configuration.

[0005] According to another aspect, a device is provided, comprising: a component for transmitting a message including a first reference signal and a first set of masks to one or more user devices; a component for receiving at least one of the following from one or more user devices: first mask channel information for each mask in the first set of masks, or a preferred side link positioning reference signal configuration based on the first mask channel information; and a component for determining a first side link positioning reference signal configuration based at least in part on the first mask channel information or the preferred side link positioning reference signal configuration.

[0006] According to another aspect, a method is provided, the method comprising: transmitting a message comprising a first reference signal and a first set of masks to one or more user devices; receiving at least one of the following from one or more user devices: first mask channel information of each mask in the first set of masks, or a preferred side link positioning reference signal configuration based on the first mask channel information; and determining a first side link positioning reference signal configuration based at least in part on the first mask channel information or the preferred side link positioning reference signal configuration.

[0007] According to another aspect, a computer program is provided, comprising instructions which, when executed by an apparatus, cause the apparatus to perform at least the following: transmit a message comprising a first reference signal and a first set of masks to one or more user devices; receive at least one of the following from one or more user devices: first mask channel information for each mask in the first set of masks, or a preferred side link positioning reference signal configuration based on the first mask channel information; and determine a first side link positioning reference signal configuration based at least in part on the first mask channel information or the preferred side link positioning reference signal configuration.

[0008] According to another aspect, a computer-readable medium is provided, which includes program instructions, which when executed by an apparatus causes the apparatus to perform at least the following: transmit a message including a first reference signal and a first set of masks to one or more user devices; receive at least one of the following from one or more user devices: first mask channel information for each mask in the first set of masks, or a preferred side link positioning reference signal configuration based on the first mask channel information; and determine a first side link positioning reference signal configuration based at least in part on the first mask channel information or the preferred side link positioning reference signal configuration.

[0009] According to another aspect, a non-transitory computer-readable medium is provided, which includes program instructions, which when executed by an apparatus causes the apparatus to perform at least the following: transmit a message including a first reference signal and a first set of masks to one or more user devices; receive at least one of the following from one or more user devices: first mask channel information for each mask in the first set of masks, or a preferred side link positioning reference signal configuration based on the first mask channel information; and determine a first side link positioning reference signal configuration based at least in part on the first mask channel information or the preferred side link positioning reference signal configuration.

[0010] According to another aspect, a device is provided, comprising at least one processor and at least one memory storing instructions which, when executed by the at least one processor, cause the device to at least: apply a first set of masks to a first reference signal; measure first mask channel information of each mask in the first set of masks from the first reference signal to which the first set of masks is applied; and transmit at least one of the following to a user equipment: the first mask channel information, or a first side link positioning reference signal configuration based on the first mask channel information.

[0011] According to another aspect, a device is provided, comprising: a component for applying a first set of masks to a first reference signal; a component for measuring first mask channel information of each mask in the first set of masks from the first reference signal to which the first set of masks is applied; and a component for transmitting at least one of the following to a user equipment: the first mask channel information, or a first side link positioning reference signal configuration based on the first mask channel information.

[0012] According to another aspect, a method is provided, the method comprising: applying a first set of masks to a first reference signal; measuring first mask channel information of each mask in the first set of masks from the first reference signal to which the first set of masks is applied; and transmitting at least one of the following to a user equipment: the first mask channel information, or a first side link positioning reference signal configuration based on the first mask channel information.

[0013] According to another aspect, a computer program is provided, comprising instructions that, when executed by an apparatus, cause the apparatus to perform at least the following: apply a first set of masks to a first reference signal; measure first mask channel information of each mask in the first set of masks from the first reference signal to which the first set of masks is applied; and transmit at least one of the following to a user equipment: the first mask channel information, or a first side link positioning reference signal configuration based on the first mask channel information.

[0014] According to another aspect, a computer-readable medium is provided, comprising program instructions which, when executed by an apparatus, cause the apparatus to perform at least the following: apply a first set of masks to a first reference signal; measure first mask channel information of each mask in the first set of masks from the first reference signal to which the first set of masks is applied; and transmit at least one of the following to a user equipment: the first mask channel information, or a first side link positioning reference signal configuration based on the first mask channel information.

[0015] According to another aspect, a non-transitory computer-readable medium is provided, which includes program instructions that, when executed by an apparatus, cause the apparatus to perform at least the following: apply a first set of masks to a first reference signal; measure first mask channel information of each mask in the first set of masks from the first reference signal to which the first set of masks is applied; and transmit at least one of the following to a user equipment: the first mask channel information, or a first side link positioning reference signal configuration based on the first mask channel information. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Hereinafter, various example embodiments will be described in more detail with reference to the accompanying drawings, in which Figure 1 An example of a cellular communication network is shown; Figure 2An example of a sidelink positioning scenario is shown; Figure 3 shows a signaling diagram according to an example embodiment; Figure 4 shows a signaling diagram according to an example embodiment; Figure 5 shows a signaling diagram according to an example embodiment; Figure 6 shows a flow chart according to an example embodiment; Figure 7 shows a flow chart according to an example embodiment; Figure 8 An example of a reference signal in a time slot is shown; Fig. 9 An example of a message is shown; and Fig.10 An example of an apparatus is shown. DETAILED DESCRIPTION

[0017] The following embodiments are exemplary. Although the specification may refer to "one", "an" or "some" embodiments in several places in the text, this does not necessarily mean that the same embodiment is referenced each time, or that a particular feature only applies to a single embodiment. Individual features of different embodiments may also be combined to provide other embodiments.

[0018] In the following, different example embodiments will be described as examples of the following using the following: an access architecture to which the example embodiments may be applied, a radio access architecture based on Long Term Evolution Advanced (LTE-Advanced, LTE-A), New Radio (NR, 5G), beyond 5G or sixth generation (6G), without limiting the example embodiments to such architectures. It is obvious to a person skilled in the art that the example embodiments may also be applied to other kinds of communication networks with suitable means 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, 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.

[0019] Figure 1An example of a simplified system architecture showing some elements and functional entities is depicted, all of which are logical units, the implementation of which may differ from what is shown. Figure 1 The connections shown are logical connections; the actual physical connections may be different. It will be apparent to those skilled in the art that the system may also include in addition to Figure 1 Other functions and structures than those shown.

[0020] However, the exemplary embodiments are not limited to the systems given as examples, but a person skilled in the art may apply the solutions to other communication systems provided with the necessary properties.

[0021] Figure 1 The example of FIG. 1 shows a portion of an exemplary radio access network.

[0022] 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)) on one or more communication channels in a radio cell, thereby providing a radio cell. The physical link from the user equipment to the access node can be called an uplink (UL) or reverse link, and the physical link from the access node to the user equipment can be called a downlink (DL) or forward link. The user equipment can also communicate directly with another user equipment via sidelink (SL) communications. It should be understood that the access node or its functionality can be implemented by using any node, host, server or access point entity suitable for this purpose.

[0023] 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 the purpose. These links may be used for signal communication purposes and also for routing data from one access node to another access node. An access node may be a computing device configured to control the radio resources of a communication system coupled thereto. 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 may be provided from the transceiver of the access node to an antenna unit that 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 can be connected on the CN side may be a serving gateway (S-GW, routing and forwarding user data packets), a packet data network gateway (P-GW) for providing user equipment with connectivity to external packet data networks, a user plane function (UPF), a mobility management entity (MME) or an access and mobility management function (AMF), etc.

[0024] 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, policy, and billing to other network functions in the core network and to other entities requesting the location of terminal devices. The AMF may receive and manage location requests from several sources: mobile originated location requests (MO-LR) from user equipment and mobile terminated location 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 location service to trigger a positioning session. The LMF may then perform positioning upon receiving such a request from the AMF. The LMF may manage the resources and timing of positioning activities. The LMF may request the location 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 via N1 for UE-based or UE-assisted positioning. Positioning may include an estimate of the location, and in addition, the LMF may also estimate the movement or accuracy of the location information upon request. In terms of connection, the AMF may be between the access node and the LMF, and is therefore closer to the access node than the LMF.

[0025] A user equipment illustrates one type of apparatus to which resources on the air interface may be allocated and assigned, and thus any features described herein with a user equipment may be implemented with a corresponding apparatus, such as a relay node.

[0026] An example of such a relay node may be a layer 3 relay towards an access node (self-backhaul relay). A self-backhaul relay node may also be referred to as an integrated access and backhaul (IAB) node. An IAB node may include two logical parts: a mobile terminal (MT) part, which is responsible for the backhaul link (i.e., the link between the IAB node and the donor node, also referred to as the parent node); and a distributed unit (DU) part, which is responsible for the access link (i.e., the sub-link between the IAB node and the user equipment) and / or the sub-link between the IAB node and other IAB nodes (multi-hop scenario).

[0027] Another example of such a relay node may be a layer 1 relay referred to as a repeater. A 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.

[0028] 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), just to mention some 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, multimedia device, reduced capability (Red Cap) device, wireless sensor device or any device integrated in a vehicle.

[0029] It should be understood that the user device may also be an almost exclusive uplink-only device, an example of which may be a camera or video camera that loads images or video clips to a network. The user device may also be a device with the ability to operate in an Internet of Things (IoT) network, which is a scenario in which objects may 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 may also utilize the cloud. In some applications, the user device may include a small portable or wearable device with a radio component (such as a watch, headset, or glasses), and the calculation may be performed in the cloud or in another user device. The user device (or in some example embodiments, a layer 3 relay node) may be configured to perform one or more user device functions.

[0030] 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, processor microcontrollers, etc.) embedded in physical objects at different locations. Mobile cyber-physical systems, in which the physical systems 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.

[0031] Additionally, although the device has been depicted as a single entity, different units, processors and / or memory units may be implemented. Figure 1 Not all are shown).

[0032] 5G enables the use of multiple input-multiple output (MIMO) antennas. Many more base stations or nodes than LTE (the so-called small cell concept), including macro sites that operate in collaboration with smaller stations and adopt various radio technologies according to service needs, 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 communication (mMTC), including vehicle safety, different sensors, and real-time control). 5G can have multiple radio interfaces. That is, below 6GHz, cmWave, and mmWave, and can also be integrated with existing traditional radio access technologies (such as LTE). At least in the early stages, integration with LTE can be implemented as a system in which macro coverage can be provided by LTE, and 5G radio interface access can be aggregated from small cells. 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 considered for use in 5G networks may be network slicing, in which multiple independent and dedicated virtual subnetworks (network instances) can be created within essentially the same infrastructure to run services with different requirements for latency, reliability, throughput and mobility.

[0033] 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 need to bring content close to the radio, which leads to local interruptions and multi-access edge computing (MEC). 5G may enable analysis and knowledge generation to occur 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, tablet computers and sensors. MEC can provide a distributed computing environment for application and service hosting. It can also have the ability to store and process content near cellular subscribers to obtain faster response times. Edge computing can cover a wide variety of technologies, such as wireless sensor networks, mobile data acquisition, mobile signature analysis, collaborative distributed peer-to-peer self-organizing networking, and can also be classified as local cloud / fog computing and grid / grid computing, open-air computing, mobile edge computing, micro-cloud, distributed data storage and retrieval, autonomous self-healing networks, remote cloud services, augmented and virtual reality, data caching, Internet of Things (large-scale connectivity and / or latency critical), critical communications (autonomous vehicles, traffic safety, real-time analysis, time-critical control, healthcare applications) processing.

[0034] The communication system may also be capable of communicating with, or utilizing 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.

[0035] The edge cloud can be brought into the radio access network (RAN) by leveraging network function virtualization (NFV) and software defined networking (SDN). Using edge cloud can mean access node operations to be performed at least partially in a server, host or node operably coupled to a remote radio head (RRH) or radio unit (RU) or an access node including a radio part. The node operations can also be distributed among multiple servers, nodes or hosts. The application of cloud RAN architecture enables RAN real-time functions to be performed on the RAN side (in distributed units DU 105), while non-real-time functions are performed in a centralized manner (in centralized units CU 108).

[0036] It should also be understood that the functional distribution between core network operations and access node operations may be different from that of 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 may be designed to support multiple layers, where MEC servers may be placed between the core and access nodes. It should be understood that MEC may also be applied to 4G networks.

[0037] 5G can also make use of non-terrestrial communications. For example, satellite communications, to enhance or supplement the coverage of 5G services, for example by providing backhaul. Possible use cases may be to provide service continuity for machine-to-machine (M2M) or Internet of Things (IoT) devices or for passengers on vehicles, or to ensure service availability for critical communications and future rail / sea / air communications. Satellite communications can make use of geostationary earth orbit (GEO) satellite systems, but also low earth orbit (LEO) satellite systems, in particular megaconstellations (systems in which hundreds of (nano) satellites are deployed). A given satellite 106 in a megaconstellation can cover several satellite-supporting network entities that create a ground cell. A ground cell can be created by a ground relay node or by an access node 104 located on the ground or in a satellite.

[0038] 6G networks are expected to adopt flexible decentralized and / or distributed computing systems and architectures and ubiquitous computing, where local spectrum licensing, spectrum sharing, infrastructure sharing and intelligent automation management are determined by mobile edge computing, artificial intelligence, short packet communication and blockchain technology. Key features of 6G may include management and control functions of intelligent connections, programmability, integrated sensing and communication, reduced energy usage, trusted infrastructure, scalability and affordability. In addition to these, 6G also targets new use cases that cover the integration of positioning and sensing capabilities into system definitions to unify user experience across the physical and digital worlds.

[0039] 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 eNodeB or a Home gNodeB.

[0040] In addition, the access node can also be divided into: a radio unit (RU), including a radio transceiver (TRX), i.e., a transmitter (Tx) and a receiver (Rx); one or more distributed units (DU), which can be used for so-called layer 1 (L1) processing and real-time layer 2 (L2) processing; and a central unit (CU) (also called a centralized unit), which can be used for non-real-time 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 achieve the centralization of the CU relative to the cell site and the DU, while the DU can be more distributed and can even be retained at the cell site. The CU and DU together can also be referred to as a baseband or baseband unit (BBU). The CU and DU can also be included in a radio access point (RAP).

[0041] A CU may be defined as a logical node that hosts higher layer protocols of an access node, such as radio resource control (RRC), service data adaptation protocol (SDAP), and / or packet data convergence protocol (PDCP). A DU may be defined as a logical node that hosts the radio link control (RLC), medium access control (MAC), and / or physical (PHY) layers of an access node. The operation of a DU may be at least partially controlled by a CU. A CU may include a control plane (CU-CP), which may be defined as a logical node that hosts the RRC and control plane portions of the PDCP protocol for a CU of an access node. A CU may also include a user plane (CU-UP), which may be defined as a logical node that hosts the user plane portions of the PDCP protocol and SDAP protocol for a CU of an access node.

[0042] The cloud computing platform can also be used to run the CU and / or DU. The CU can run in the cloud computing platform, which can be referred to as a virtualized CU (vCU). In addition to the vCU, there can also be a virtualized DU (vDU) running in the cloud computing platform. In addition, there can also be a combination in which the DU can use a so-called bare metal solution, such as an application-specific integrated circuit (ASIC) or a customer-specific standard product (CSSP) system-on-chip (SoC) solution. It should also be understood that the functional distribution between the above-mentioned access node units or different core network operations and access node operations may be different.

[0043] In addition, in the geographical area of ​​the 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), a large cell with a diameter of up to tens of kilometers, or a smaller cell, such as a micro cell, a femto cell or a pico cell. Figure 1An access node may provide any of these cells. A cellular radio system may be implemented as a multi-layer network comprising several types of radio cells. In a multi-layer network, one access node may provide one type of radio cell or multiple types of radio cells, so multiple access nodes may be needed to provide such a network structure.

[0044] 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. A network that can use "plug and play" access nodes can also include, in addition to the home eNodeB or home gNodeB, a home node B gateway or HNB-GW ( Figure 1 (not shown). The HNB-GW, which may be installed in an operator's network, may aggregate services from a large number of home eNodeBs or home gNodeBs back to the core network.

[0045] Positioning techniques can be used to estimate the physical location of a user equipment. The user equipment to be positioned is referred to as a target UE or target user equipment. For example, the positioning techniques used in NR may be based on at least one of the following: time difference of arrival (TDoA), round trip time (RTT), angle of departure (AoD) and / or angle of arrival (AoA).

[0046] In wireless positioning, multiple positioning anchor points in a known position can send and / or receive one or more positioning reference signals (PRS) to / from the target UE. In the uplink, a sounding reference signal (SRS) can be used as a positioning reference signal. For example, multi-point positioning techniques can then be used to determine the position of the target UE relative to the positioning anchor point (i.e., locate the target UE). The positioning anchor point may also be referred to as an anchor point, anchor node, multi-point positioning anchor point, or reference point in this article. The positioning anchor point can be, for example, a radio access node (e.g., a gNB) or a transmit and receive point (TRP) (in uplink / downlink positioning) or other UE (in sidelink positioning).

[0047] Sidelink (SL) positioning refers to a positioning method in which the target UE utilizes a sidelink (i.e., a direct device-to-device link) to locate itself either absolutely (in the case of absolute positioning) or relatively (in the case of relative positioning). For UE-assisted positioning, the target UE may utilize a sidelink to obtain positioning measurements and report the measurements to a network entity, such as a location management function (LMF). Sidelink positioning may also be used to obtain ranging information.

[0048] Ranging means determining the distance between two UEs and / or the direction of one UE to another UE via a direct device connection.

[0049] Absolute positioning refers to estimating the position of a target UE in two-dimensional or three-dimensional geographic coordinates (eg, latitude, longitude, and / or altitude) within a coordinate system.

[0050] Relative positioning refers to estimating the position of the target UE relative to other network elements or relative to other UEs.

[0051] SL positioning may be based on the transmission of a sidelink positioning reference signal (SL PRS) by multiple anchor UEs, wherein the SL PRS is received and measured by the target UE to enable positioning of the target UE within the precise latency and accuracy requirements of the corresponding SL positioning session. Alternatively or additionally, the target UE may transmit a SL PRS to be received and measured by the anchor UE.

[0052] An anchor UE may be defined as a UE that supports positioning of a target UE, for example by sending and / or receiving reference signals (e.g., SL PRS) over the SL interface for positioning. This may be similar to UL / DL based positioning, where a gNB may be used as an anchor to send and / or receive reference signals to / from a target UE for positioning.

[0053] SL PRS refers to a reference signal sent on the SL for positioning purposes.

[0054] Figure 2 An example of a sidelink positioning scenario is shown, where the target UE 200 is performing a sidelink positioning session, i.e., exchanging SL PRS with two anchor UEs 201, 202 in order to determine its position. Here, the anchor UEs 201, 202 are referred to as providing SL PRS assistance (including SL PRS) to the target UE 200.

[0055] Some example use cases for sidelink positioning may include (but are not limited to) vehicle-to-everything (V2X), public safety, commercial, and industrial IoT (IIoT).

[0056] One of the advantages of sidelink positioning comes into play when the target UE needs to be located outside the network coverage, or in scenarios using a limited number of radio access nodes or TRPs as positioning anchors. That is, sidelink positioning can be considered as a solution to improve the availability of positioning, for example, when Uu positioning is not available (e.g., the target UE is out of coverage), and when Global Navigation Satellite System (GNSS) signals are not available (e.g., in places like tunnels, heavy urban scenarios, etc.).

[0057] With sidelink positioning, the target UE can leverage other UEs (or, for example, roadside units with SL interface) used as positioning anchors on SL. With SL, the target UE can be located in limited coverage or out-of-coverage scenarios. Roadside Units (RSUs) can be defined as UE-type or gNB-type fixed infrastructure entities that support, for example, V2X applications.

[0058] When at least two UEs participate in sidelink positioning, three network coverage scenarios can be considered (in coverage, partial coverage, and out of coverage). Taking two UEs as an example, the in-coverage scenario refers to the situation where both UEs are in network coverage. Partial coverage means that one UE remains in network coverage, but the other UE is out of network coverage. The out-of-coverage scenario refers to the situation where both UEs are out of network coverage. The UE can switch between the in-coverage, partial coverage, and out-of-coverage scenarios. For example, there may be V2X and public safety use cases that may require positioning when there is no network coverage and GNSS coverage.

[0059] For example, for IIoT use cases in out-of-coverage scenarios, there may be some positioning accuracy requirements. Positioning requirements can be captured via key performance indicators (KPIs) such as horizontal and vertical accuracy, positioning service availability, positioning service latency, time to first fix (TTFF), update rate, energy consumption, etc.

[0060] Vertical accuracy may refer to height accuracy and may determine floors for indoor usage and differentiate between superimposed tracks for road and rail usage (eg, bridges).

[0061] Location service availability may be defined as the amount of time that the location service delivers the required location-related data within the performance requirements divided by the percentage value of the amount of time the system is expected to deliver the location service according to specifications in the target service area.

[0062] Location service latency may be defined as the time elapsed between an event triggering the determination of location-related data and the availability of the location-related data at a system interface.

[0063] TTFF may be defined as the time elapsed between an event that first triggers the determination of location-related data and the availability of the location-related data at the positioning system interface.

[0064] Performance requirements may be defined for different positioning service levels. Along with horizontal and vertical accuracy requirements, requirements for positioning service availability and positioning service latency may be very stringent for positioning service levels 4 (99% availability and 15ms latency) and 6 (99% availability and 10ms latency).

[0065] Examples of scenarios or use cases for positioning service levels 4 and 6 may include V2X, Set 2, and Set 3 use cases. This may correspond to lane-level positioning requirement use cases such as vehicle platooning, cooperative lane merging, lane change warning, emergency break warning, intersection movement assistance, etc., and to below-meter positioning requirement use cases such as high-definition sensor sharing, vulnerable road user (VRU)-collision risk warning, cooperative maneuvering in emergency situations, real-time situation awareness, and high-definition maps, etc.

[0066] For IIoT, examples of scenarios or use cases for location service levels 4 and 6 may include aspects of future scenarios such as augmented reality in smart factories, mobile control panels with safety functions in smart factories (within factory hazardous areas), inbound logistics for manufacturing (for driving trajectories if supported by other sensors such as cameras, GNSS, inertial measurement units for indoor autonomous driving systems).

[0067] The SL PRS may be configured according to various parameters. For example, the SL PRS (pre) configuration may refer to the (pre) configured parameters of the SL PRS, such as the time-frequency resources including its bandwidth and periodicity; parameters related to directionality, such as beam direction, beam width, number of beams; and transmit power, etc.

[0068] In coverage or partial coverage scenarios, the SL PRS (pre) configuration can be determined by the network (e.g., LMF or gNB). In out-of-coverage scenarios, the SL PRS (pre) configuration can be autonomously pre-configured and / or determined by the UE.

[0069] A Resource Pool (RP) is a set of resources allocated for the SL process. There are two types of RPs: Receive Resource Pool (Rx RP) and Transmit Resource Pool (Tx RP). These can be signaled by the gNB for in-coverage situations or pre-configured for out-of-coverage situations.

[0070] To send and receive data or control signaling over SL, the UE can utilize one of the following resource allocation modes: NR SL Mode 1 (network controlled mode) or NR SL Mode 2 (UE autonomous mode). In NR SL Mode 1, the network allocates SL resources to the UE. In NR SL Mode 2, the UE autonomously selects SL resources based on a sensing mechanism.

[0071] For NR SL mode 1, the UE may need to be in RRC_CONNECTED state. For NR SL mode 2, in addition to the possibility of operating in RRC_CONNECTED state, the UE may also be in RRC_INACTIVE or RRC_IDLE state (e.g. when out of coverage).

[0072] NR SL transmissions may utilize a demodulation reference signal (DMRS) to enable the receiver UE to decode the associated SL physical channel, i.e., the physical sidelink control channel (PSCCH), the physical sidelink shared channel (PSSCH), or the physical sidelink broadcast channel (PSBCH). Here, the DMRS is transmitted within the associated sidelink physical channel.

[0073] To demodulate the PSCCH, a DMRS may be transmitted within the PSCCH. The PSCCH DMRS may follow the design of the DMRS associated with the PDCCH in Rel.15NR Uu. The PSCCH DMRS may reuse the same pseudo-random sequence for the PDCCH DMRS in Rel.15NR Uu, where the PSCCH DMRS sequence initialization is based on a (pre-)configured value for each resource pool. In addition, each PSCCH symbol may contain a PSCCH DMRS. The pattern of the PSCCH DMRS in the frequency domain may also reuse the DMRS frequency pattern for the PDCCH in Rel.15NR Uu.

[0074] To demodulate the PSSCH, a DMRS may be transmitted within the PSSCH. The design of the PSSCH DMRS may follow some aspects of the DMRS associated with the physical uplink shared channel (PUSCH) in Rel.15 NR Uu and others from the PDSCH DMRS. The PSSCH DMRS may reuse the pseudo-random sequence used for the Rel. PUSCH DMRS, where the sequence initialization is based on a (pre-)configured value for each resource pool. In the frequency domain, a type 1 pattern configuration of the PDSCH DMRS may be used for the PSSCH DMRS.

[0075] To support different channel conditions, the DMRS associated with the PSSCH may be carried on different symbols within a PSSCH slot, i.e., in 2, 3 or 4 SL symbols, i.e., with different time patterns. The different time patterns for the PSSCH DMRS may depend on the number of symbols for PSCCH, the number of symbols with PSSCH DMRS and the number of PSSCH symbols within a slot. The time patterns currently supported for PSSCH DMRS in NR SL are listed in Table 1 below, where the position of the DMRS symbol is indicated by Here, l dis the duration of the transmission scheduling resources for the PSSCH and the associated PSCCH, including replicated Orthogonal Frequency Division Multiplexing (OFDM) symbols. For a resource pool, one or more time patterns for the PSSCH DMRS may be (pre)configured. In case multiple patterns are (pre)configured, the DMRS time pattern used in the PSSCH may be indicated in the associated first stage Sidelink Control Information (SCI). Table 1

[0076] As described above, SL positioning can be based on the exchange of SL PRS between the target UE and the anchor UE (for example, in RTT-based positioning techniques), or the transmission of SL PRS by multiple anchor UEs to be received by the target UE (for example, in TDoA-based positioning techniques), so as to enable the target UE to be positioned within the precise latency and accuracy requirements of the corresponding SL positioning session. Here, the SL PRS reception quality at the anchor UE (in RTT-based techniques) and / or at the target UE can be a key factor in determining the achievable latency and accuracy performance of the SL positioning use case. Therefore, the resource configuration for SL PRS transmission should ensure the expected SL PRS reception quality. In the following, the RTT-based SL positioning technique is regarded as an example.

[0077] Note that in Uu-positioning, the LMF selects, for example, the bandwidth (BW), the comb structure (frequency pattern) of the bandwidth, and the repetition (number of consecutive symbols) based on a rough position estimate of the target UE. In other words, the LMF may know the worst-case conditions that the target UE may experience and measure the PRS accordingly, e.g., denser time allocation under poor signal-to-interference-plus-noise ratio (SINR) conditions, a comb structure proportional to the coherence bandwidth, etc.

[0078] Unlike Uu-positioning, in SL positioning, there may be no central entity (e.g., LMF) that knows the SL channel conditions and has control over the SL PRS configuration. Therefore, the target UE and / or anchor UE may need to autonomously select the SL PRS configuration for its SLPRS transmission (e.g., in RTT-based or TDoA-based schemes). In this regard, there are challenges in how the target UE selects the appropriate SL PRS configuration for a given anchor UE, especially when the target UE is unaware of the channel towards the anchor UE (e.g., in the initial phase of the SL positioning session). Although the target UE can select the most conservative SL PRS configuration to ensure high SLPRS reception quality, this may be resource-inefficient and therefore may not scale well in, for example, denser UE deployment scenarios.

[0079] Some example embodiments may provide a method by which a target UE may select or adapt a SL PRS configuration to the link conditions between itself and a given anchor UE. The method may implement a closed-loop type method for tuning the SL PRS configuration to the propagation and interference conditions specific to a given radio link between a target UE and an anchor UE.

[0080] Some example embodiments may provide improved SL resource utilization (because the most conservative SL PRS configuration does not need to be applied to ensure high SL PRS reception quality), low latency, and high-accuracy SL positioning (because high SL PRS reception quality can be ensured even in the early stages of a SL positioning session).

[0081] For example, some example embodiments may consider an RTT-based SL positioning scheme, in which the SL PRS is exchanged between the target UE and the anchor UE, and the target UE determines the SL PRS configuration. However, it should be noted that the problem and solution may be applicable to any SL positioning technology, in which the anchor UE, the target UE and / or the third UE (in which the neighboring third UE provides IUC-like information) need to select the SL PRS configuration (for its own SL PRS transmission or to provide IUC-like information to other UEs transmitting SL PRS). IUC is an abbreviation for inter-UE coordination. In order to determine the appropriate SL PRS configuration suitable for the radio link conditions between the target UE and a given anchor UE, mask channel information (MCI) determined based on the SL PRS configuration may be utilized. Here, a set of RS masks may be defined on a set of reference signals (RS) to be transmitted between the target UE and the anchor UE, wherein a given RS mask is designed to simulate the SL PRS, and thus the RS mask simulates the effect of sending multiple differently configured SL PRSs, i.e., with different time / frequency / spatial patterns and densities.

[0082] However, some example embodiments are described below using the principles and terminology of 5G technology without limiting the example embodiments to 5G communication systems.

[0083] Figure 3 A signaling diagram according to an example embodiment is shown. In this example embodiment, a SL PRS configuration is selected at the target UE for its own SL PRS transmission. During the (re)establishment of a SL positioning session, the target UE transmits a message with a reference signal (RS) and a set of RS masks to the candidate anchor UE. The candidate anchor UE then applies the mask to the RS to calculate the MCI for each mask and responds to the target UE with the MCI. The MCI is used by the target UE to select the SL PRS configuration for its own SL PRS transmission.

[0084] refer to Figure 3 In block 301, a SL positioning session initiation is triggered at the target UE. This may be due to the positioning requirements of the use case involved (e.g., V2X). For example, the target UE may consider RTT-based SL positioning techniques.

[0085] In block 302, the target UE determines an RS mask configuration including at least a first set of masks (RS masks) that, when applied to a first reference signal at a candidate anchor UE, emulates a SL PRS having multiple different sidelink positioning reference signal (SL PRS) configurations. In other words, the RS mask is defined to emulate the SL PRS when applied to the first reference signal, and different RS masks emulate the effect of sending differently configured SL PRSs, i.e., with different time, frequency, and spatial patterns and densities. The mask helps the target UE anticipate how a given SL PRS configuration will affect the accuracy of subsequent SL positioning measurements / estimations.

[0086] For example, the target UE may determine a first set of masks based on coarse ranging information to the candidate anchor UE (if previous SL communication occurred). Otherwise, the target UE may select a mask by incrementally masking the resources from a minimum masking mode to a maximum masking mode, where the minimum and maximum may be established based on the minimum or maximum coherence time and bandwidth. For example, for a minimum coherence bandwidth (expressed as minB), minFreq comb = minB. Similarly, for a minimum coherence time (expressed as minTcoh), minTime comb = minTcoh. A comb structure may refer to a pattern defined in one or more of: a time domain (e.g., a symbol), a frequency domain (e.g., a subcarrier), and / or one or more spatial domains (e.g., a beam).

[0087] Herein, SL PRS configuration may refer to a set of parameters that establish an RS pattern in at least the following domains: frequency, time, and space (eg, transmit beam and / or receive beam).

[0088] A given mask in the first set of masks may include a binary (Boolean) matrix that, when applied to the matrix of the first reference signal (RS sample matrix), masks one or more entries (i.e., some entries) of the matrix of the first reference signal. The binary matrix (mask) may be a two-dimensional matrix or a multidimensional matrix. That is, the binary matrix (mask) may include two or more dimensions.

[0089] Let M represent a first set of masks determined by the target UE, where the i-th entry M(i) describes how the i-th mask should be generated and applied to the first reference signal. For example, a given mask M(i) in the first set of masks can be defined by a combination of at least the following: a comb structure in the time domain, a comb structure in the frequency domain, and a comb structure in the spatial domain. The comb structure in the time domain can mean a time pattern, such as selecting every x-th symbol of the first reference signal. The comb structure in the frequency domain can mean a frequency pattern, such as selecting every x-th subcarrier of the first reference signal for symbol (x). The comb structure in the spatial domain can mean a spatial pattern, such as selecting transmit beams b1, b2, ... and receive beams r1, r3, ... for symbol (x).

[0090] In other words, if the entry in the mask is 1, that is, M(i)[f,x,b,r] = 1, the RS samples at frequency f, symbol x, transmit beam b, and receive beam r will be used to calculate MCI(i). Conversely, if the entry is 0, the corresponding RS samples are not used when calculating MCI(i). Here, the term "symbol" may refer to an OFDM symbol.

[0091] The following provides non-limiting examples of application masks: Wherein f1 and f2 may represent the index of the number of subcarriers, and t1 and t2 may represent the index of the number of OFDM symbols or the number of samples.

[0092] In block 303, the target UE sends a request to one or more candidate anchor UEs ( Figure 3 Only one anchor UE is shown, and other UEs are not shown, but they may exist) transmits a message including a first reference signal and a first set of masks. In this document, the term "candidate anchor UE" may refer to a UE that is not yet active in the SL positioning session of the target UE. In other words, one or more candidate anchor UEs may not have transmitted a SL PRS to the target UE or measured a SL PRS transmitted by the target UE. For example, the first reference signal may include a DMRS.

[0093] The message may also include a request to measure and report MCI using the first set of masks.The MCI that has been measured by using the first set of masks may also be referred to herein as first mask channel information.

[0094] The message can be transmitted as a SL broadcast message on a configured SL time slot, where some symbols are used for RS transmission and other symbols carry data. The data symbol payload may include: a SL positioning request (and session KPIs, such as latency targets); the type of positioning technology used in the SL positioning session (e.g., TDoA, RTT, etc.); a first set of masks M, where the i-th entry M(i) describes how the i-th mask should be generated and applied to the RS portion of the SL signal; and a request to measure MCI using a mask in the first set of masks M.

[0095] For example, in order to initiate an RTT-based SL positioning technique, the target UE may send an anchor discovery solicitation message represented as Msg-A to find / discover a suitable anchor UE nearby. In order to provide an RS mask configuration (a first set of masks) to one or more candidate anchor UEs, in Msg-A, the target UE may include the mask configuration. In addition, the SL PRS (from which different SL PRS configurations can be obtained by using a mask) may be embedded in the Msg-A. In addition, the target UE may embed a request for the candidate anchor UE to respond using the MCI in the Msg-A. In other words, a message including a first reference signal and a first set of masks (and a request) may refer to an anchor discovery solicitation message (Msg-A). Fig. 9 An example of the structure of Msg-A is shown in FIG.

[0096] In block 304, one or more candidate anchor UEs receive the request, decode the payload, and evaluate the request. In the case of a positive result (i.e., if a given candidate anchor UE determines that the SL positioning session of the target UE is supported), the candidate anchor UE applies the first set of masks to the first reference signal according to the indicated mask configuration to measure or calculate first mask channel information for each mask in the first set of masks from the first reference signal to which the first set of masks is applied.

[0097] The first masked channel information may include at least one of: a reference signal received power (RSRP), a received signal strength indicator (RSSI), a channel frequency response (CFR), or a channel impulse response (CIR) measured from a first reference signal having a first set of masks applied (ie, combined).

[0098] Applying the first set of masks to the first reference signal may include applying a binary matrix of each mask to the matrix of the first reference signal, e.g., by multiplying the binary matrix (mask) with the matrix of the first reference signal. That is, the indicated masks (i.e., binary (Boolean) matrices) are combined over the matrix of RS samples of the first reference signal, e.g., as described above for block 302. Figure 8An example of applying a masked RS is shown in . On the masked RS samples (when applying the mask M on the RS as instructed), the candidate anchor UE measures or calculates the MCI for each mask M(i).

[0099] For example, a given candidate anchor UE may sample the first reference signal and arrange the samples in a matrix Mrs, where Mrs(f, t, s, r) specifies the RS samples at time t, subcarrier f, transmit beam s, and receive beam r. For a given mask "i", the candidate anchor UE may calculate the mask RS matrix Mmrs = Mrs x M(i) and use Mmrs to extract MCI(i).

[0100] In block 305, (if the evaluation has a positive result) one or more candidate anchor UEs transmit the first mask channel information to the target UE. A given candidate anchor UE may respond to the request with a SL unicast message, where the payload of the message may be encoded with: the location and location certainty of the candidate anchor UE, and the first mask channel information MCI(i) for each mask M(i).

[0101] For example, a given candidate anchor UE may respond to the request in Msg-A by sending an anchor discovery response message denoted as Msg-B to the target UE (e.g., in a unicast manner). In Msg-B, the candidate anchor UE may include at least: its own position and position certainty, and the first mask channel information MCI(i) for each mask M(i).

[0102] Alternatively or additionally, one or more candidate anchor UEs may determine a preferred SL PRS configuration based on the first mask channel information and transmit the preferred SL PRS configuration to the target UE instead of the first mask channel information or in addition to the first mask channel information.

[0103] In other words, one or more candidate anchor UEs may transmit at least one of the following to the target UE: first mask channel information, or a preferred sidelink positioning reference signal configuration based on the first mask channel information. The preferred sidelink positioning reference signal configuration may also be referred to as a first sidelink positioning reference signal configuration.

[0104] In block 306, the target UE performs anchor UE selection, for example based on the received Msg-B. In other words, the target UE may select at least one anchor UE from one or more candidate anchor UEs to support its SL positioning session.

[0105] In block 307, the target UE determines or selects a first sidelink positioning reference signal configuration based at least in part on the first masked channel information (e.g., RSRP, RSSI, CFR and / or CIR, etc.) received from the selected at least one anchor UE or based on the preferred sidelink positioning reference signal configuration received from the selected at least one anchor UE. In this way, the target UE can determine or select a SL PRS configuration suitable for a radio link between the target UE and the at least one selected anchor UE.

[0106] The first sidelink positioning reference signal configuration may also be determined based at least in part on a mapping of the first mask channel information to one or more sidelink positioning reference signal parameter settings. In other words, the target UE may use the received MCI list and the internal mapping between the MCI and the SL PRS parameter settings to select a suitable SL PRS configuration for the anchor UE. For example, the mapping may be given in a tabular form as shown in Table 2 below. In Table 2, the positioning requirement level (e.g., Pos_Req_1, Pos_Req_2, etc.) captures the requirements of the positioning use case involved, such as positioning accuracy requirements. For a given MCI range (e.g., range 1, range 2, etc.), different accuracy requirements may be mapped to different SL PRS parameter settings (i.e., SL PRS configurations), such as frequency modes and time modes.

[0107] Such a table may be populated autonomously by the target UE, or it may be provided by the network or another UE (e.g., an anchor UE or a neighboring UE). Depending on the session type, the number of responding candidate anchor UEs, and their availability, the target UE may further refine the SL PRS parameter settings output by the table search. The table may be known to both the target UE and one or more candidate anchor UEs. In this case, one or more candidate anchor UEs may indicate their preferred SL PRS configuration instead of the MCI in box 305, or one or more candidate anchor UEs may indicate their preferred SL PRS configuration in addition to the MCI in box 305. Table 2

[0108] In block 308, the target UE transmits a first sidelink positioning reference signal to at least one selected anchor UE based on the first sidelink positioning reference signal configuration. In other words, the target UE applies the selected SL PRS configuration to its own SL PRS transmission. The at least one selected anchor UE receives and measures the first sidelink positioning reference signal to support the SL positioning session of the target UE.

[0109] Figure 4A signaling diagram according to an example embodiment is shown. In this example embodiment, a SL PRS configuration is selected at the target UE for SL PRS transmission of the anchor UE. Here, the target UE provides an RS configuration for a response message from the anchor UE. Subsequently, the anchor UE responds with a reference signal according to the indicated RS configuration. The target UE then applies the RS mask to the RS transmitted by the anchor UE to calculate the MCI. The MCI is used to select a suitable SL PRS configuration for SL PRS transmission of the anchor UE. The target UE then indicates the selected SL PRS configuration to the anchor UE so that the anchor UE can use the suitable SL PRS configuration for its SL PRS transmission.

[0110] refer to Figure 4 In block 401, a SL positioning session initiation is triggered at the target UE. This may be due to the positioning requirements of the use case involved (e.g., V2X). For example, the target UE may consider RTT-based SL positioning techniques.

[0111] In block 402, the target UE determines a reference signal configuration. The reference signal configuration may be referred to as a configuration for a first reference signal. In this document, a configuration may refer to a set of parameters that establish an RS pattern in at least the following domains: frequency, time, and space (e.g., transmit beam and / or receive beam).

[0112] In block 403, the target UE transmits a configuration for the first reference signal to one or more candidate UEs. For example, to initiate RTT-based SL positioning, the target UE may send an anchor discovery solicitation message (denoted as Msg-A) to find / discover a suitable anchor UE nearby. In Msg-A, the target UE may include the reference signal configuration determined in block 402. Msg-A may also include a request to respond using the first reference signal.

[0113] One or more candidate anchor UEs receive Msg-A, decode the payload, and evaluate the request in block 404. In case of a positive outcome (ie, if a given candidate anchor UE determines that the SL positioning session of the target UE is supported), the candidate anchor UE applies the reference signal configuration to its response message.

[0114] In block 405, (in the event that the evaluation has a positive result) one or more candidate anchor UEs respond to the target UE by transmitting a first reference signal to the target UE according to the reference signal configuration received from the target UE. For example, a given candidate anchor UE may respond to the request by sending an anchor discovery response message (denoted as Msg-B) to the target UE (e.g., in a unicast manner), wherein the Msg-B also includes the first reference signal. For example, the first reference signal may be a DMRS.

[0115] In block 406, the target UE performs anchor UE selection, for example based on the received Msg-B. In other words, the target UE may select at least one anchor UE from one or more candidate anchor UEs to support its SL positioning session.

[0116] In block 407, the target UE determines a first set of masks and applies the first set of masks to a first reference signal received from the selected at least one anchor UE, and measures first mask channel information of each mask in the first set of masks from the first reference signal to which the first set of masks is applied.

[0117] The first masked channel information may include at least one of: a reference signal received power (RSRP), a received signal strength indicator (RSSI), a channel frequency response (CFR), or a channel impulse response (CIR) measured from a first reference signal to which the first set of masks is applied.

[0118] A given mask in the first set of masks may include a binary (Boolean) matrix that, when applied to the matrix of the first reference signal (RS sample matrix), masks one or more entries (i.e., some entries) of the matrix of the first reference signal. The binary matrix (mask) may be a two-dimensional matrix or a multidimensional matrix. That is, the binary matrix (mask) may include two or more dimensions.

[0119] Let M denote a first set of masks, where the i-th entry M(i) describes how the i-th mask should be generated and applied to the first reference signal. For example, a given mask M(i) in the first set of masks can be defined by a combination of at least: a comb structure in the time domain, a comb structure in the frequency domain, and a comb structure in the spatial domain. The comb structure in the time domain can mean a time pattern, such as selecting every x-th symbol of the first reference signal. The comb structure in the frequency domain can mean a frequency pattern, such as selecting every y-th subcarrier of the first reference signal for symbol (x). The comb structure in the spatial domain can mean a spatial pattern, such as selecting transmit beams b1, b2, ... and receive beams r1, r3, ... for symbol (x).

[0120] The target UE calculates the MCI for each mask M(i) on the masked RS samples (i.e., the RS generated by applying the mask M to the received DMRS). In other words, if the entry in the mask is 1, i.e., M(i)[f,x,b,r]=1, the RS samples at frequency f, symbol x, transmit beam b, and receive beam r are used to calculate MCI(i). Conversely, if the entry is 0, the corresponding RS samples are not used in calculating MCI(i). Here, the term "symbol" may refer to an OFDM symbol.

[0121] The following provides a non-limiting example of applying a mask: Wherein f1 and f2 may represent the index of the number of subcarriers, and t1 and t2 may represent the index of the number of OFDM symbols or the number of samples.

[0122] In block 408, the target UE determines or selects a first sidelink positioning reference signal configuration based at least in part on first masked channel information measured by the target UE (e.g., RSRP, RSSI, CFR and / or CIR, etc.) In this way, the target UE may determine or select a SL PRS configuration suitable for a radio link between the target UE and the selected at least one anchor UE.

[0123] In block 409, the target UE transmits a first sidelink positioning reference signal configuration to the selected at least one anchor UE so that the selected at least one anchor UE can use a suitable SL PRS configuration for its SL PRS transmission.

[0124] In block 410, the selected at least one anchor UE transmits a sidelink positioning reference signal to the target UE based on the first sidelink positioning reference signal configuration. The target UE receives and measures the first sidelink positioning reference signal from the selected at least one anchor UE for a SL positioning session of the target UE.

[0125] Figure 5 A signaling diagram according to an example embodiment is shown. In this example embodiment, the target UE selects a SL PRS configuration for its own SL PRS transmission, and a SL PRS configuration for the SL PRS transmission of the anchor UE. Here, during the (re)establishment of the SL positioning session, the target UE sends a message with an RS, a first set of RS masks, and an RS configuration for a response message to a candidate anchor UE. The candidate anchor UE applies the mask to the RS to calculate a first MCI for each mask, and responds to the target UE with the first MCI. In addition, the response includes an RS configured according to the indicated RS. The target UE uses the received first MCI to select a suitable SL PRS configuration for its own SL PRS transmission. In addition, the target UE applies a second set of RS masks to the RS transmitted by the anchor UE to calculate a second MCI. The second MCI is used to select a suitable SL PRS configuration for the SL PRS transmission of the anchor UE. The target UE then indicates the selected SL PRS configuration to the anchor UE so that the anchor UE can use a suitable SL PRS configuration for its SL PRS transmission.

[0126] refer to Figure 5In block 501, a SL positioning session initiation is triggered at the target UE. This may be due to the positioning requirements of the use case involved (e.g., V2X). For example, the target UE may consider RTT-based SL positioning techniques.

[0127] In block 502, the target UE determines a first RS mask configuration including at least a first set of masks (RS masks) that emulates a sidelink positioning reference signal (SL PRS) having a plurality of different SL PRS configurations when applied to a first reference signal at a candidate anchor UE. In other words, the RS mask is defined to emulate the SL PRS when applied to the first reference signal, and different RS masks emulate the effect of transmitting SL PRSs of different configurations, i.e., with different time patterns, frequency patterns, and spatial patterns and densities.

[0128] In this document, SL PRS configuration may refer to a set of parameters that establish an RS pattern in at least the following domains: frequency, time, and space (e.g., transmit beam and / or receive beam).

[0129] A given mask in the first set of masks may include a binary (Boolean) matrix that, when applied to the matrix of the first reference signal (RS sample matrix), masks one or more entries (i.e., some entries) of the matrix of the first reference signal. The binary matrix (mask) may be a two-dimensional matrix or a multidimensional matrix. That is, the binary matrix (mask) may include two or more dimensions.

[0130] In block 503, the target UE determines a reference signal configuration. The reference signal configuration may be referred to as a configuration for a second reference signal.

[0131] In block 504, the target UE transmits a message including a first reference signal, a first set of masks, and a configuration for a second reference signal to one or more candidate UEs. For example, to initiate RTT-based SL positioning, the target UE may send an anchor discovery solicitation message (denoted as Msg-A) to find / discover a suitable anchor UE nearby. Msg-A may include a first reference signal, a first set of masks, and a configuration for a second reference signal. Msg-A may also include a request to respond using a second reference signal and a first MCI measured using a first set of masks. Fig. 9 An example of the structure of Msg-A is shown in Alternatively, the first reference signal, the first set of masks, the configuration for the second reference signal, and the request may be transmitted separately instead of in a single message.

[0132] In block 505, one or more candidate anchor UEs receive the Msg-A, decode the payload, and evaluate the request. In the case of a positive result (i.e., if a given candidate anchor UE determines that the SL positioning session of the target UE is supported), the candidate anchor UE applies the first set of masks to the first reference signal to measure or calculate first mask channel information for each mask in the first set of masks from the first reference signal to which the first set of masks is applied.

[0133] The first masked channel information may include at least one of: a reference signal received power (RSRP), a received signal strength indicator (RSSI), a channel frequency response (CFR), or a channel impulse response (CIR) measured from a first reference signal to which the first set of masks is applied.

[0134] Applying the first set of masks to the first reference signal may include applying a binary matrix of each mask to the matrix of the first reference signal. That is, the indicated masks (ie, binary (Boolean) matrices) are applied over the matrix of RS samples of the first reference signal. Figure 8 An example of applying a masked RS is shown in . On the masked RS samples (when applying the mask M on the RS as instructed), the candidate anchor UE measures or calculates the MCI for each mask M(i).

[0135] For example, a given candidate anchor UE may sample the first reference signal and arrange the samples in a matrix Mrs, where Mrs(f, t, s, r) specifies the RS samples at time t, subcarrier f, transmit beam s, and receive beam r. For a given mask "i", the candidate anchor UE may calculate the mask RS matrix Mmrs = Mrs x M(i) and use Mmrs to extract MCI(i).

[0136] In block 506, in case the evaluation has a positive outcome (ie, if the given candidate anchor UE determines to support the SL positioning session of the target UE), the candidate anchor UE applies the reference signal configuration to its response message.

[0137] In block 507, (in the event that the evaluation has a positive result) one or more candidate anchor UEs respond to the target UE by transmitting the first mask channel information and the second reference signal (e.g., DMRS) according to the reference signal configuration received from the target UE. For example, a given candidate anchor UE may respond to the request by sending an anchor discovery response message (denoted as Msg-B) to the target UE (e.g., in a unicast manner), where the Msg-B may include the first MCI and the second reference signal. Alternatively, the first MCI and the second reference signal may be transmitted separately rather than in a single message.

[0138] In block 508, the target UE performs anchor UE selection, for example, based on the received Msg-B. In other words, the target UE may select at least one anchor UE from one or more candidate anchor UEs to support its SL positioning session.

[0139] In block 509, the target UE determines or selects a first sidelink positioning reference signal configuration for its own SL PRS transmission based at least in part on first masked channel information (eg, RSRP, RSSI, CFR and / or CIR, etc.) received from the selected at least one anchor UE.

[0140] In block 510, the target UE applies a second set of masks to a second reference signal received from the selected at least one anchor UE, and measures second masked channel information of each mask in the second set of masks from the second set of reference signals to which the second set of masks is applied.

[0141] The second masked channel information may include at least one of: a reference signal received power (RSRP), a received signal strength indicator (RSSI), a channel frequency response (CFR), or a channel impulse response (CIR) measured from a second reference signal to which the second set of masks is applied.

[0142] A given mask in the second set of masks may include a binary (Boolean) matrix that, when applied to the matrix of the second reference signal (RS sample matrix), shields one or more entries (i.e., some entries) of the matrix of the second reference signal. The binary matrix (mask) may be a two-dimensional matrix or a multidimensional matrix. That is, the binary matrix (mask) may include two or more dimensions.

[0143] In block 511, the target UE determines or selects a second sidelink positioning reference signal configuration based at least in part on second masked channel information (eg, RSRP, RSSI, CFR, and / or CIR, etc.) measured by the target UE.

[0144] In block 512, the target UE transmits a first sidelink positioning reference signal to at least one selected anchor UE based on the first sidelink positioning reference signal configuration. In other words, the target UE applies the first SL PRS configuration to its own SLPRS transmission. At least one selected anchor UE receives and measures the first sidelink positioning reference signal to support the SL positioning session of the target UE.

[0145] In block 513, the target UE transmits a second sidelink positioning reference signal configuration to the selected at least one anchor UE so that the selected at least one anchor UE may use the second SL PRS configuration for its SL PRS transmission.

[0146] In block 514, the selected at least one anchor UE transmits a second sidelink positioning reference signal to the target UE based on the second sidelink positioning reference signal configuration received from the target UE. The target UE receives and measures the second sidelink positioning reference signal from the selected at least one anchor UE for the SL positioning session of the target UE.

[0147] Here, the terms "first sidelink positioning reference signal" and "second sidelink positioning reference signal" are used to distinguish the sidelink positioning reference signals, and they do not necessarily mean a specific order of the sidelink positioning reference signals. Similarly, the terms "first sidelink positioning reference signal configuration" and "second sidelink positioning reference signal configuration" are used to distinguish the SL PRS configurations, and they do not necessarily mean a specific order of determining the SL PRS configurations.

[0148] Figure 6 A flow chart according to an example embodiment of a method performed by an apparatus such as a user device or comprising a user device or included in a user device is shown. A user device 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 device may correspond to Figure 1 One of the user equipment 100, 102, or corresponding to Figure 2 The target UE 200.

[0149] refer to Figure 6 In block 601, a message including a first reference signal and a first set of masks is transmitted to one or more user equipments. The one or more user equipments may include one or more anchor UEs or one or more candidate anchor UEs.

[0150] In block 602, at least one of the following is received from one or more user equipments: first mask channel information for each mask in a first set of masks, or a preferred sidelink positioning reference signal configuration based on the first mask channel information.

[0151] In block 603, a first sidelink positioning reference signal configuration is determined based at least in part on the first mask channel information or the preferred sidelink positioning reference signal configuration.

[0152] Figure 7 A flow chart according to an example embodiment of a method performed by an apparatus such as or including a user equipment or included in a user equipment is shown. A user equipment may also be referred to as a subscriber unit, a mobile station, a remote terminal, an access terminal, a user terminal, a terminal device, a user equipment (UE), an anchor UE, a candidate anchor UE, a target UE, or a target user equipment. A user equipment may correspond to Figure 1 One of the user equipment 100, 102, or corresponding to Figure 2, or corresponding to the target UE 200 Figure 2 One of the anchor UEs 201, 202.

[0153] refer to Figure 7 In block 701, a first set of masks is applied to a first reference signal. In this context, applying the first set of masks to the first reference signal may mean combining the first reference signal with a given mask in the first set of masks.

[0154] In block 702, first mask channel information for each mask in a first set of masks is measured from a first reference signal to which the first set of masks is applied.

[0155] In block 703, at least one of the following is transmitted to a user equipment (eg, to a target UE or an anchor UE): first mask channel information, or a first sidelink positioning reference signal configuration based on the first mask channel information.

[0156] Above through Figures 3 to 7 The described blocks, related functions and information exchanges (messages) are not in absolute chronological order, and some of them may be executed simultaneously or in an order different from the described order. Other functions may also be executed between or within them, and other information may be sent and / or other rules may apply. Some blocks or parts of blocks or one or more pieces of information may also be omitted or replaced by corresponding blocks or parts of blocks or one or more pieces of information.

[0157] As used herein, “at least one of: ” and “at least one of ” and similar expressions (wherein a list of two or more elements is connected by “and” or “or”) refer to at least any one of the elements, or at least any two or more of the elements, or at least all of the elements.

[0158] Figure 8 An example of an RS pattern for a SL signal is shown, on which a mask may be applied to obtain masked RS samples emulating SLPRS of different configurations. Figure 8 In FIG. 8 , a given black box 801 represents a resource element (RE) carrying an RS.

[0159] Fig. 9 An example of the structure 900 of Msg-A is shown, where the PSCCH duration is 2 symbols, the number of PSSCH DMRS is 4, and there is a guard period (k d )), where PSSCH-DMRS is used as SLPRS. Fig. 9In Msg-A, the PSSCH symbol with DMRS is shown as DMRS. In Msg-A, together with the anchor discovery solicitation message, the payload transmitted in the PSSCH symbol may, for example, include at least: RS mask configuration (a set of masks M), and a request to measure MCI using a mask in the set of masks M. MCI may mean any combination of the following: RSRP, RSSI, CFR, CIR, etc. Fig. 9 In the invention, AGC is an abbreviation of automatic gain control, and AGC is used to adjust signal strength. Fig. 9 The numbers 0-13 in refer to symbols in the time domain.

[0160] Fig.10 Instructions include the Figures 3 to 7 An example of an apparatus 1000 including any of the methods of the present invention or any other example embodiments described above. For example, the apparatus 1000 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 One of the user equipment 100, 102, or Figure 2 One of the user equipments 200, 201, 202. 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, a candidate anchor UE, a target UE, or a target user equipment.

[0161] The apparatus 1000 includes at least one processor 1010. The at least one processor 1010 interprets instructions (or computer program instructions) and processes data. The at least one processor 1010 may include one or more programmable processors. The at least one processor 1010 may include programmable hardware with embedded firmware, and may alternatively or additionally include one or more application specific integrated circuits (ASICs).

[0162] At least one processor 1010 is coupled to at least one memory 1020. At least one processor is configured to read data from at least one memory 1020 and write data to at least one memory 1020. At least one 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, one or more non-volatile memory cells, or alternatively, one or more volatile memory cells. Volatile memory may be, for example, random access memory (RAM), dynamic random access memory (DRAM) or synchronous dynamic random access memory (SDRAM). Non-volatile memory may be, for example, read-only memory (ROM), programmable read-only memory (PROM), electrically erasable programmable read-only memory (EEPROM), flash memory, optical storage or magnetic storage. In general, memory may be referred to as non-transitory computer-readable medium. The term "non-transitory" as used herein is a limitation of the medium itself (i.e., tangible, not a signal), rather than a limitation of data storage persistence (e.g., RAM to ROM). At least one memory 1020 stores computer readable instructions that are executed by at least one processor 1010 to perform one or more of the above-described example embodiments. For example, non-volatile memory stores computer readable instructions, and at least one processor 1010 executes instructions using volatile memory to temporarily store data and / or instructions. Computer readable instructions may refer to computer program code.

[0163] The computer readable instructions may be pre-stored to at least one memory 1020, or alternatively or additionally, they may be received by the device via an electromagnetic carrier signal and / or may be copied from a physical entity such as a computer program product. The execution of the computer readable instructions by at least one processor 1010 causes the device 1000 to perform one or more of the above-described example embodiments. That is, at least one processor and at least one memory storing instructions may provide means for providing or causing the execution of any of the above-described methods and / or blocks.

[0164] In the context of this document, "memory" or "computer-readable media" or "a computer-readable medium" may be any one or more non-transitory media or components 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). The term "non-transitory" as used herein is a limitation on the medium itself (i.e., tangible, not a signal), not on data storage persistence (e.g., RAM versus ROM).

[0165] The device 1000 may also include an input unit 1030 or be connected to the input unit 1030. The input unit 1030 may include one or more interfaces for receiving input. The one or more interfaces may include, for example, one or more temperature, motion and / or orientation sensors, one or more cameras, one or more accelerometers, one or more microphones, one or more buttons and / or one or more touch detection units. In addition, the input unit 1030 may include an interface to which an external device may be connected.

[0166] The device 1000 may also include an output unit 1040. The output unit may include or be connected to one or more displays capable of presenting visual content, such as a light emitting diode (LED) display, a liquid crystal display (LCD), and / or a liquid crystal on silicon (LCoS) display. The output unit 1040 may also include one or more audio outputs. The one or more audio outputs may be, for example, a speaker.

[0167] The device 1000 also includes a connection unit 1050. The connection unit 1050 implements a wireless connection to one or more external devices. The connection unit 1050 includes at least one transmitter and at least one receiver that can be integrated into the device 1000 or the device 1000 can be connected to. At least one transmitter includes at least one transmitting antenna, and at least one receiver includes at least one receiving antenna. The connection unit 1050 may include an integrated circuit or a group of integrated circuits that provide wireless communication capabilities for the device 1000. Alternatively, the wireless connection can be a hardwired application-specific integrated circuit (ASIC). The connection unit 1050 can also provide components for performing at least some of the blocks of one or more of the example embodiments described above. The connection unit 1050 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 (demodulator) modulator, and / or an encoder / decoder circuit.

[0168] It should be noted that the apparatus 1000 may further include Fig.10 Various components not described in the specification. The various components may be hardware components and / or software components.

[0169] 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 (e.g., an implementation only in analog and / or digital circuitry); and b) a combination of hardware circuitry and software, such as (if applicable): i) a combination of analog and / or digital hardware circuitry and software / firmware; and ii) any portion of a hardware processor with software (including a digital signal processor, software and memory that work together to enable a device such as a mobile phone to perform various functions); and c) a hardware circuit and / or processor, such as a microprocessor or a portion of a microprocessor, that requires software (e.g., firmware) for operation, but the software may not be present when not required for operation.

[0170] 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 (or their) accompanying software and / or firmware. For example and if applicable to the 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.

[0171] The techniques and methods described herein can be implemented in various ways. For example, these techniques can be implemented in hardware (one or more devices), firmware (one or more devices), software (one or more modules), or a combination thereof. For hardware implementations, the apparatus of the example embodiments may 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 performed by a module of at least one chipset (e.g., a process, a function, etc.) that performs the functions described herein. The software code can be stored in a memory unit and executed by a processor. The memory unit can be implemented within a processor or outside a processor. In the latter case, it can be communicatively coupled to the processor via various components known in the art. In addition, 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, as will be understood by those skilled in the art.

[0172] 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 can be varied 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 comprising at least one processor and at least one memory, wherein the at least one memory stores instructions, which when executed by the at least one processor cause the apparatus to at least: transmitting a message including a first reference signal and a first set of masks to one or more user equipments; receiving, from the one or more user equipments, at least one of: first mask channel information for each mask in the first set of masks, or a preferred sidelink positioning reference signal configuration based on the first mask channel information; as well as A first sidelink positioning reference signal configuration is determined based at least in part on the first mask channel information or the preferred sidelink positioning reference signal configuration.

2. The apparatus according to claim 1, further configured to: The first set of masks is determined, and the first set of masks, when applied to the first reference signal, emulates sidelink positioning reference signals having multiple different configurations.

3. An apparatus according to any preceding claim, wherein a mask in the first set of masks comprises a binary matrix which, when applied to the matrix of the first reference signal, masks one or more entries of the matrix of the first reference signal. 4 . The apparatus according to claim 3 , wherein the mask is defined by a combination of at least: a comb structure in the time domain, a comb structure in the frequency domain, and a comb structure in the spatial domain.

5. The apparatus according to any preceding claim, further configured to: A request is transmitted to the one or more user equipments to measure the first masked channel information using the first set of masks.

6. An apparatus according to any preceding claim, wherein the first masked channel information comprises at least one of: a reference signal received power measured from the first reference signal to which the first set of masks is applied, a received signal strength indicator, a channel frequency response or a channel impulse response.

7. An apparatus according to any preceding claim, wherein the first sidelink positioning reference signal configuration is determined at least in part based on a mapping of the first mask channel information to one or more sidelink positioning reference signal parameter settings.

8. The apparatus according to any preceding claim, further configured to: A first sidelink positioning reference signal is transmitted based on the first sidelink positioning reference signal configuration.

9. The apparatus according to any preceding claim, further configured to: transmitting a configuration for a second reference signal to the one or more user equipments; receiving the second reference signal from the one or more user equipments; applying a second set of masks to the second reference signal; measuring second mask channel information for each mask in the second set of masks from the second reference signal to which the second set of masks is applied; determining a second sidelink positioning reference signal configuration based at least in part on the second masked channel information; transmitting the second sidelink positioning reference signal configuration to the one or more user equipments; as well as Based on the second sidelink positioning reference signal configuration, a second sidelink positioning reference signal is received from the one or more user equipments.

10. An apparatus comprising at least one processor and at least one memory, wherein the at least one memory stores instructions that, when executed by the at least one processor, cause the apparatus to at least: applying a first set of masks to a first reference signal; measuring first mask channel information for each mask in the first set of masks from the first reference signal to which the first set of masks is applied; as well as Transmit at least one of the following to the user equipment: the first mask channel information, or a first sidelink positioning reference signal configuration based on the first mask channel information.

11. The apparatus of claim 10, wherein the masks in the first set of masks comprise binary matrices, and applying the first set of masks to the first reference signal comprises: The binary matrix of each mask is applied to the matrix of the first reference signal.

12. The device according to any one of claims 10 to 11, further configured to: receiving a message including the first reference signal and the first set of masks from the user equipment; and Based on the first mask channel information or the first sidelink positioning reference signal configuration, a first sidelink positioning reference signal is received from the user equipment.

13. The device according to any one of claims 10 to 12, further configured to: receiving, from the user equipment, a configuration for a second reference signal; transmitting the second reference signal to the user equipment based on the configuration; receiving a second sidelink positioning reference signal configuration from the user equipment; as well as Based on the second sidelink positioning reference signal configuration, a second sidelink positioning reference signal is transmitted to the user equipment.

14. The apparatus according to any one of claims 10 to 11, further configured to: Transmitting a configuration for the first reference signal to the user equipment; receiving the first reference signal from the user equipment; and The first sidelink positioning reference signal configuration is determined based at least in part on the first mask channel information measured for each mask in the first set of masks.

15. A method comprising: transmitting a message including a first reference signal and a first set of masks to one or more user equipments; receiving, from the one or more user equipments, at least one of: first mask channel information for each mask in the first set of masks, or a preferred sidelink positioning reference signal configuration based on the first mask channel information; as well as A first sidelink positioning reference signal configuration is determined based at least in part on the first mask channel information or the preferred sidelink positioning reference signal configuration.

16. A method comprising: applying a first set of masks to a first reference signal; measuring first mask channel information for each mask in the first set of masks from the first reference signal to which the first set of masks is applied; as well as Transmit at least one of the following to the user equipment: the first mask channel information, or a first sidelink positioning reference signal configuration based on the first mask channel information.

17. A non-transitory computer readable medium comprising program instructions, which when executed by an apparatus causes the apparatus to at least perform the following: transmitting a message including a first reference signal and a first set of masks to one or more user equipments; receiving at least one of the following from the one or more user equipments: first mask channel information for each mask in the first set of masks, or a preferred sidelink positioning reference signal configuration based on the first mask channel information; and A first sidelink positioning reference signal configuration is determined based at least in part on the first mask channel information or the preferred sidelink positioning reference signal configuration.

18. A non-transitory computer readable medium comprising program instructions, which when executed by a device cause the device to at least: applying a first set of masks to a first reference signal; measuring first mask channel information of each mask in the first set of masks from the first reference signal to which the first set of masks is applied; and Transmit at least one of the following to the user equipment: the first mask channel information, or a first sidelink positioning reference signal configuration based on the first mask channel information.

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