GB2629640A

GB2629640A - Indicating absolute location information or network node storing absolute location information

Info

Publication number: GB2629640A
Application number: GB2306658.2A
Authority: GB
Inventors: Kucera Stepan
Original assignee: Nokia Technologies Oy
Current assignee: Nokia Technologies Oy
Priority date: 2023-05-05
Filing date: 2023-05-05
Publication date: 2024-11-06
Also published as: GB202306658D0; CN121100536A; WO2024231068A1

Abstract

There is provided an apparatus comprising: at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the apparatus at least to perform: generating a sidelink, SL, discovery message indicating that absolute location information, being indicative of an absolute location of the apparatus, is available 302; transmitting the SL discovery message at least to a terminal device 304; and indicating, to the terminal device, at least one of the absolute location information or a network node storing the absolute location information 306. The SL discovery message may comprises a location status information element indicating that the absolute location of the apparatus is available. The SL discovery message may further indicate that the absolute location information is valid for a certain time. In another embodiment, an apparatus for: obtaining absolute location information indicating absolute location of a first terminal device; and requesting the first terminal device to transmit, based on the requesting, or based on a further request via a second terminal device, SL discovery message indicating that the absolute location information is available, is disclosed.

Description

INDICATING ABSOLUTE LOCATION INFORMATION OR NETWORK NODE STORING ABSOLUTE LOCATION INFORMATION

TECHNICAL FIELD

Various example embodiments relate generally to cellular communications. More particularly, the various examples relate to indicating absolute location information or network node storing the absolute location information in sidelink positioning.

BACKGROUND

Sidelink positioning (or sideling localization) is a procedure for determining location of terminal device or terminal devices based at least on transmitting one or more reference signals between different UEs. Relative positioning or localization may be performed without absolute location information, but absolute positioning or localization may require absolute location of other UE(s) to be known. Hence, it may be beneficial to provide solutions that enable sharing of absolute location information in sidelink communication system.

BRIEF DESCRIPTION

According to some aspects, there is provided the subject matter of the independent claims. Some further aspects are defined in the dependent claims. The embodiments that do not fall under the scope of the claims are to be interpreted as

examples useful for understanding the disclosure.

LIST OF THE DRAWINGS

In the following, the invention will be described in greater detail with reference to the embodiments and the accompanying drawings, in which Figure 1 presents a network to which one or more embodiments are applicable; Figure 2 shows an example of sidelink positioning to which one or more embodiments are applicable; Figures 3A, 3B, 4, 5A, 5B, 5C, 6A, 6B, 6C, and 7 illustrate some example embodiments; and Figures 8 and 9 illustrate apparatuses according to some embodiments.

DESCRIPTION OF EMBODIMENTS

The following embodiments are exemplary. Although the specification may refer to "an", "one", or "some" embodiment(s) in several locations of the text, this does not necessarily mean that each reference is made to the same embodiment(s), or that a particular feature only applies to a single embodiment. Single features of different embodiments may also be combined to provide other embodiments. For the purposes of the present disclosure, the phrases "at least one of A or B", "at least one of A and B", "A and/or B" means (A), (B), or (A and B). For the purposes of the present disclosure, the phrases "A or B" and "A and/or B" means (A), (B), or (A and B). For the purposes of the present disclosure, the phrase "A, B, and/or C" means (A), (B), (C), (A and B), (A and C), (B and C), or (A, B, and C).

It shall be understood that although the terms "first" and "second" etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, a first element could be termed a second element, and similarly, a second element could be termed a first element, without departing from the scope of example embodiments.

Embodiments described may be implemented in a radio system, such as one comprising at least one of the following radio access technologies (RATs): Worldwide Interoperability for Micro-wave Access (WiMAX), Global System for Mobile communications (GSM, 2G), GSM EDGE radio access Network (GERAN), General Packet Radio Service (GRPS), Universal Mobile Telecommunication System (UMTS, 3G) based on basic wideband-code division multiple access (W-CDMA), high-speed packet access (HSPA), Long Term Evolution (LTE), LTE-Advanced, and enhanced LTE (eLTE). Term 'eLTE' here denotes the LTE evolution that connects to a 5G core. LTE is also known as evolved UMTS terrestrial radio access (EUTRA) or as evolved UMTS terrestrial radio access network (EUTRAN). A term "resource" may refer to radio resources, such as a physical resource block (PRB), a radio frame, a subframe, a time slot, a subband, a frequency region, a sub-carrier, a beam, etc. The term "transmission" and/or "reception" may refer to wirelessly transmitting and/or receiving via a wireless propagation channel on radio resources The embodiments are not, however, restricted to the systems/RATs given as an example but a person skilled in the art may apply the solution to other communication systems/networks provided with necessary properties. Some examples of a suitable communication networks include a 5G network and/or a 6G network. The 3GPP solution to 5G is referred to as New Radio (NR). 6G is envisaged to be a further development of 5G. NR has been envisaged to use multiple-input-multiple-output (MIMO) multi-antenna transmission techniques, more base stations or nodes than the current network deployments of LTE (a so-called small cell concept), including macro sites operating in co-operation with smaller local area access nodes and perhaps also employing a variety of radio technologies for better coverage and enhanced data rates. 5G will likely be comprised of more than one radio access technology / radio access network (RAT/RAN), each optimized for certain use cases and/or spectrum. 5G mobile communications may have a wider range of use cases and related applications including video streaming, augmented reality, different ways of data sharing and various forms of machine type applications, including vehicular safety, different sensors and real-time control. 5G is expected to have multiple radio interfaces, namely below 6GHz, cmWave and mmWave, and being integrable with existing legacy radio access technologies, such as the LTE.

The current architecture in LTE networks is distributed in the radio and centralized in the core network. The low latency applications and services in SG may require to bring the content close to the radio which leads to local break out and multi-access edge computing (MEC). 5G enables analytics and knowledge generation to occur at the source of the data. This approach requires leveraging resources that may not be continuously connected to a network such as laptops, smartphones, tablets and sensors. MEC provides a distributed computing environment for application and service hosting. It also has the ability to store and process content in close proximity to cellular subscribers for faster response time. Edge computing covers a wide range of technologies such as wireless sensor networks, mobile data acquisition, mobile signature analysis, cooperative distributed peer-to-peer ad hoc networking and processing also classifiable as local cloud/fog computing and grid/mesh computing, dew computing, mobile edge computing, cloudlet, distributed data storage and retrieval, autonomic self-healing networks, remote cloud services, augmented and virtual reality, data caching, Internet of Things (massive connectivity and/or latency critical), critical communications (autonomous vehicles, traffic safety, real-time analytics, time-critical control, healthcare applications). Edge cloud may be brought into RAN by utilizing network function virtualization (NVF) and software defined networking (SDN). Using edge cloud may mean access node operations to be carried out, at least partly, in a server, host or node operationally coupled to a remote radio head or base station comprising radio parts. Network slicing allows multiple virtual networks to be created on top of a common shared physical infrastructure. The virtual networks are then customised to meet the specific needs of applications, services, devices, customers or operators.

In radio communications, node operations may in be carried out, at least partly, in a central/centralized unit, CU, (e.g. server, host or node) operationally coupled to distributed unit, DU, (e.g. a radio head/node). It is also possible that node operations will be distributed among a plurality of servers, nodes or hosts. It should also be understood that the distribution of work between core network operations and base station operations may vary depending on implementation. Thus, 5G networks architecture may be based on a so-called CU-DU split. One gNB-CU controls several gNB-DUs. The term dgNB' may correspond in SG to the eNB in LTE. The gNBs (one or more) may communicate with one or more UEs. The gNBCU (central node) may control a plurality of spatially separated gNB-DUs, acting at least as transmit/receive (Tx/Rx) nodes. In some embodiments, however, the gNBDUs (also called DUI may comprise e.g. a radio link control (RLC), medium access control (MAC) layer and a physical (PHY) layer, whereas the gNB-CU (also called a CU) may comprise the layers above RLC layer, such as a packet data convergence protocol (PDCP) layer, a radio resource control (RRC) and an internet protocol (IP) layers. Other functional splits are possible too. It is considered that skilled person is familiar with the 051 model and the functionalities within each layer.

In an embodiment, the server or CU may generate a virtual network through which the server communicates with the radio node. In general, virtual networking may involve a process of combining hardware and software network resources and network functionality into a single, software-based administrative entity, a virtual network. Such virtual network may provide flexible distribution of operations between the server and the radio head/node. In practice, any digital signal processing task may be performed in either the CU or the DU and the boundary where the responsibility is shifted between the CU and the DU may be selected according to implementation.

Some other possible technology advancements to be used are Software-Defined Networking (SDN), Big Data, and all-IP, to mention only a few non-limiting examples. For example, network slicing may be a form of virtual network architecture using the same principles behind software defined networking (SDN) and network functions virtualisation (NFV) in fixed networks. SDN and NFV may deliver greater network flexibility by allowing traditional network architectures to be partitioned into virtual elements that can be linked (also through software).

Network slicing allows multiple virtual networks to be created on top of a common shared physical infrastructure. The virtual networks are then customised to meet the specific needs of applications, services, devices, customers or operators. The plurality of gNBs (access points/nodes), each comprising the CU and one or more DUs, may be connected to each other via the Xn interface over 5 which the gNBs may negotiate. The gNBs may also be connected over next generation (NG) interfaces to a 5G core network (5GC), which may be a 5G equivalent for the core network of LTE. Such 5G CU-DU split architecture may be implemented using cloud/server so that the CU having higher layers locates in the cloud and the DU is closer to or comprises actual radio and antenna unit. There are 10 similar plans ongoing for LTE/LTE-A/eLTE as well. When both eLTE and SG will use similar architecture in a same cloud hardware (HW), the next step may be to combine software (SW) so that one common SW controls both radio access networks/technologies (RAN/RAT). This may allow then new ways to control radio resources of both RANs. Furthermore, it may be possible to have configurations where the full protocol stack is controlled by the same HW and handled by the same radio unit as the CU.

It should also be understood that the distribution of labour between core network operations and base station operations may differ from that of the LTE or even be non-existent. Some other technology advancements probably to be used are Big Data and all-IP, which may change the way networks are being constructed and managed. SG (or new radio, NR) networks are being designed to support multiple hierarchies, where MEC servers can be placed between the core and the base station or nodeB (gNB). It should be appreciated that MEC can be applied in 4G networks as well.

5G may also utilize satellite communication to enhance or complement the coverage of SG service, for example by providing backhauling. Possible use cases are providing service continuity for machine-to-machine (M2M) or Internet of Things (loT) devices or for passengers on board of vehicles, or ensuring service availability for critical communications, and future rail- way/maritime/aeronautical communications. Satellite communication may utilize geostationary earth orbit (GEO) satellite systems, but also low earth orbit (LEO) satellite systems, in particular mega-constellations (systems in which hundreds of (nano)satellites are deployed). Each satellite in the mega-constellation may cover several satellite-enabled network entities that create on-ground cells. The on-ground cells may be created through an on-ground relay node or by a gNB located on-ground or in a satellite.

The embodiments may be also applicable to narrow-band (NB) Internet-of-things (loT) systems which may enable a wide range of devices and services to be connected using cellular telecommunications bands. NB-loT is a narrowband radio technology designed for the Internet of Things (loT) and is one of technologies standardized by the 3rd Generation Partnership Project (3GPP).

Other 3GPP loT technologies also suitable to implement the embodiments include machine type communication (MTC) and eMTC (enhanced Machine-Type Communication). NB-loT focuses specifically on low cost, long battery life, and enabling a large number of connected devices. The NB-1°T technology is deployed "in-band" in spectrum allocated to Long Term Evolution (LTE) -using resource blocks within a normal LTE carrier, or in the unused resource blocks within a LTE carrier's guard-band -or "standalone" for deployments in dedicated spectrum. The embodiments may be also applicable to device-to-device (D2D), machine-to-machine, peer-to-peer (P2P) communications. The embodiments may be also applicable to vehicle-to-vehicle (V2V), vehicle-to-infrastructure (V2I), infrastructure-to-vehicle (I2V), or in general to V2X or X2V communications. Figure 1 illustrates an example of a communication system to which embodiments of the invention may be applied. The system may comprise a control node 110 providing one or more cells, such as cell 100, and a control node 112 providing one or more other cells, such as cell 102. Each cell may be, e.g., a macro cell, a micro cell, femto, or a pico cell, for example. In another point of view, the cell may define a coverage area or a service area of the corresponding access node. The control node 110, 112 may be an evolved Node B (eNB) as in the LTE and LTE-A, ng-eNB as in eLTE, gNB of SG, or any other apparatus capable of controlling radio communication and managing radio resources within a cell. The control node 110, 112 may be called a base station, network node, or an access node.

The system may be a cellular communication system composed of a radio access network of access nodes, each controlling a respective cell or cells. The access node 110 may provide user equipment (UE) 120 (one or more UEs) with wireless access to other networks such as the Internet. The wireless access may comprise downlink (DL) communication from the control node to the UE 120 and uplink (UL) communication from the UE 120 to the control node.

Additionally, although not shown, one or more local area access nodes may be arranged such that a cell provided by the local area access node at least partially overlaps the cell of the access node 110 and/or 112. The local area access node may provide wireless access within a sub-cell. Examples of the sub-cell may include a micro, pico and/or femto cell. Typically, the sub-cell provides a hot spot within a macro cell. The operation of the local area access node may be controlled by an access node under whose control area the sub-cell is provided. In general, the control node for the small cell may be likewise called a base station, network node, or an access node.

There may be one or more UEs 120, 122 in the system. UE(s) 120, 122 may be served by one or more control nodes 110, 112. The UE(s) 120, 122 may communicate with each other, for example, using D2D communication interface established between them. D2D communication may refer to, for example, sidelink (SL) communication, such as NR sidelink communication.

The term "terminal device" or "UE" refers to any end device that may be capable of wireless communication, more particularly cellular wireless communication. By way of example rather than limitation, a terminal device may also be referred to as a communication device, user equipment (UE), a Subscriber Station (SS), a Portable Subscriber Station, a Mobile Station (MS], or an Access Terminal (AT). The terminal device may include, but not limited to, a mobile phone, a cellular phone, a smart phone, voice over IP (VolP) phones, wireless local loop phones, a tablet, a wearable terminal device, a personal digital assistant (PDA), portable computers, desktop computer, image capture terminal devices such as digital cameras, gaming terminal devices, music storage and playback appliances, vehicle-mounted wireless terminal devices, wireless endpoints, mobile stations, laptop-embedded equipment (LEE), laptop-mounted equipment (LME), USB dongles, smart devices, wireless customer-premises equipment (CPE), an Internet of Things (loT) device, a watch or other wearable, a head-mounted display (HMD), a vehicle, a drone, a medical device and applications (e.g., remote surgery), an industrial device and applications (e.g., a robot and/or other wireless devices operating in an industrial and/or an automated processing chain contexts), a consumer electronics device, a device operating on commercial and/or industrial wireless networks, and the like. In the following description, the terms "terminal device", "communication device", "terminal", "user equipment" and "UE" may be used interchangeably.

In the case of multiple access nodes in the communication network, the access nodes may be connected to each other with an interface. LTE specifications call such an interface as X2 interface. For IEEE 802.11 network (i.e. wireless local area network, WLAN, WiFi), a similar interface may be provided between access points. An interface between an LTE access point and a SG access point, or between two 5G access points may be called Xn. Other communication methods between the access nodes may also be possible. The access nodes 110 and 112 may be further connected via another interface to a core network 116 of the cellular communication system. The LTE specifications specify the core network as an evolved packet core (EPC), and the core network may comprise a mobility management entity (MME) and a gateway node. The MME may handle mobility of terminal devices in a tracking area encompassing a plurality of cells and handle signalling connections between the terminal devices and the core network. The gateway node may handle data routing in the core network and to/from the terminal devices. The 5G specifications specify the core network as a 5G core (5GC), and there the core network may comprise e.g. an access and mobility management function (AMF) and a user plane function/gateway (UPF), to mention only a few. The AMF may handle termination of non-access stratum (NAS) signalling, NAS ciphering & integrity protection, registration management, connection management, mobility management, access authentication and authorization, security context management. The UPF node may support packet routing & forwarding, packet inspection and QoS handling, for example.

6G networks are expected to adopt flexible decentralized and/or distributed computing systems and architecture and ubiquitous computing, with local spectrum licensing, spectrum sharing, infrastructure sharing, and intelligent automated management underpinned by mobile edge computing, artificial intelligence, short-packet communication and blockchain technologies. Key features of 6G will include intelligent connected management and control functions, programmability, integrated sensing and communication, reduction of energy footprint, trustworthy infrastructure, scalability and affordability. In addition to these, 6G is also targeting new use cases covering the integration of localization and sensing capabilities into system definition to unifying user experience across physical and digital worlds.

The one or more UEs 120, 122 of the cellular communication system of Figure 1 may support sidelink positioning. In sidelink positioning, positioning is a positioning technique used, e.g., in 5G NR communication networks. In sidelink positioning, signals transmitted over sidelink (i.e., between UEs) are used for calculating the location of a given UE. When a UE determines a need for sidelink positioning, it may first determine which potential anchor UEs (i.e., UEs which may serve as reference points in the positioning calculations) are in range, and then, select one or more of these anchor UEs for performing the triangulation or other actions necessary for determining the position. The location of the target UE may be determined at the target UE, at location management function (LMF) (can sometimes be referred to as location server or sensing server), and/or at some other UE supporting the target UE or acting as LMF. The location determination may be based at least on the measurement(s) on one or more positioning reference signals (PRS) transmitted between the anchor UE(s) and the target UE.

For example, to enable anchor UE to indicate whether it's location is known, Sidelink Positioning Protocol (SLPP) metadata field may be included in sidelink discovery message to indicate whether or not the location is known. For example, such indication could be a flag or binary indicator: "location is known" or "location is not known". Thus, potential target UE(s) may determine whether or not the anchor UE's location is known and thus determine whether it can be used in determining the target UE's location (can be referred to also target UE's position). Target UE's location with respect to the anchor UE(s) can be calculated based on measuring one or more reference signals (PRS and/or SRS) transmitted between the anchor UE(s) and the target UEs. In order to compute absolute location of the target UE, absolute location of the anchor UE(s) may be needed to know (i.e., utilizing multi-lateration w.r.t. located anchor UEs). Thus, the indication from anchor UE may indicate whether or not the absolute location of the anchor UE is known. If absolute location of an anchor UE is known, said UE may be referred to as "located UE", for example.

Some simple examples on how to compute/determine location of the target UE 120 is shown. Referring to Figure 2, according to first example, the target UE 120 may measure PRSs (i.e. SL PRSs) transmitted by the anchor UEs 122, 222 via sidelink communication links 202, 204. Accordingto second example, the target UE 120 may transmits PRS(s) (i.e. SL PRS(s)) to the anchor UEs 122, 222 via sidelink communication links 202, 204. Combination of first and second examples may be possible to use.

The transmitted PRS(s) may be measured e.g. to obtain direction (e.g. angle of arrival (A0A)) and strength (e.g. received signal strength indicator (RSS1)) information. Based on said information and information on location information on the anchor UEs 122, 222, the absolute location of the target UE 120 may be determined. In one example, the absolute location of the target UE 120 may be determined at the target UE 120. In one example, the absolute location of the target UE 120 may be determined at the location management entity 250 (e.g. LMF or UE acting as LMF (e.g. referred to as server UE)). In such case, the measurement(s) on the PRS(s) may be shared with the location management entity 250. However, it has not been proposed how the indication (location is known/location is not known) should be provided between the UEs and how the indication should be utilized for determining the absolute location of the anchor UE at the entity who will determine the absolute location of the target UE. Hence, solution is proposed for enabling providing absolute location information on the anchor UE(s).

Figures 3A and 3B illustrate flow diagrams according to some embodiments. Referring to Figure 3A, a method for an apparatus of radio access network (RAN), such as cellular communication network, is proposed. The apparatus may be or be comprised in a UE, such as UE 120, 122, 222 of Figure 1 and/or 2. For the sake of simplicity, apparatus performing method of Figure 3A is herein referred to as UE 122. Thus, the apparatus may be capable of acting as an anchor UE for sidelink positioning. In some examples, UE 122 may be referred to as located UE (LUE). That is, UE 122 may be an LUE if its absolute location is known e.g. by the UE 122 or by LME 250.

According to an embodiment, the method of Figure 3A comprises: generating an SL discovery message indicating that absolute location information, being indicative of an absolute location of the apparatus, is available (block 302); transmitting the SL discovery message at least to a terminal device (block 304); and indicating, to the terminal device, the absolute location information and/or a network node storing the absolute location information (block 306).

The SL discovery message may be transmitted to one or more terminal devices. For example, the SL discovery message may be broadcasted by the UE 122, and other UEs may receive the broadcasted SL discovery message. In the example, the SL discovery message is transmitted to at least one UE (referred to above as terminal device). The terminal device may be referred to hereinafter as UE 120 which may be a target UE (tUE) that needs to be located via SL positioning (session based or sessionless SL positioning).

The solution herein proposes that SL discovery message may be used to indicate that UE 122 location is known (i.e. location information is available and indicates that absolute location of the UE 122 is known). For example, the indication may be a flag or a bit indicator indicating that location information is available. On the other hand, if the location information is not available, the UE 122 may transmit an SL discovery message indicating that location information is not available or not transmit SL discovery message at all. It may be beneficial to also transmit SL discovery message indicating that location information is not available since such UE may still enable relative positioning to be performed. However, absolute location of the UE 122 (and possibly some other UEs to increase accuracy of the positioning) may be needed to perform absolute positioning of the target UE 120. In addition, the solution proposes that absolute location information on the UE 122 or network node storing the absolute location information on the UE 122 is indicated, by the UE 122, to the target UE 120. Thus, the target UE 120 may directly obtain the absolute location information, or the target UE 120 may request the location information from the indicated network node storing the absolute location information. Thus, target UE 120 may obtain the absolute location information on the UE 122 which may then be used in absolute positioning of the target UE 120. As described with reference to Figure 2, the absolute location of the anchor UE(s) may be needed for determining absolute location of the target UE.

The indication of the absolute location information and/or the network node storing the absolute location information may be done in multiple ways. For example, the SL discovery message transmitted in block 304 may be used to convey such information. Other examples include sharing the information as encrypted information (using one or more ciphering key(s)), via radio resource control (RRC) signalling, via Sidelink Positioning Protocol (SLPP) signalling, via LTE positioning protocol (LPP) signalling, and/or as assistance data. The indicated absolute location information and/or the indication of the network node may include a validity indicator (e.g. a timer and/or timestamp) indicating validity time of the indicated information. For example, the absolute location information may be indicated to be valid for a certain time. In another example, the absolute location information may be associated with a time stamp indicating the time when the absolute location of the UE 122 was obtained. Thus, the UE 120 may determine how long said information is valid based on the time stamp and some (pre) configuration, for example.

Absolute location information may indicate or be indicative of absolute location of the UE with which the absolute location information is associated. For example, absolute location information on the UE 122 may indicate absolute location of the UE at least in some point in time. Accuracy of the absolute location may depend on the method used for positioning the UE 122 and/or time passed after the positioning has been performed. The absolute location information may indicate the absolute location, for example, as coordinates. For example, the coordinates may be 2-dimensional or 3-dimensional. For example, the coordinates may indicate latitude, longitude, and/or elevation.

Referring to Figure 4, a method for an apparatus of radio access network (RAN), such as cellular communication network, is proposed. The apparatus may be or be comprised in a UE, such as UE 120, 122, 222 of Figure 1 and/or 2. For the sake of simplicity, apparatus performing method of Figure 4 is herein referred to as UE 120. Thus, the apparatus may be capable of acting as a target UE for sidclink positioning. I.e. the UE 120 may need to be positioned (or located) at some point.

According to an embodiment, the method of Figure 4 comprises: receiving, from a terminal device (e.g. UE 122), an SL discovery message indicating that absolute location information, being indicative of an absolute location of the terminal device (e.g. UE 122), is available (block 312); obtaining, from the terminal device (e.g. UE 122), the absolute location information or an indication of a network node storing the absolute location information (block 314); and utilizing the absolute location information and/or the indication of the network node storing the absolute location information for determining a location of the apparatus (block 316).

Obtaining step 312 may correspond to transmitting step 304 of Figure 3A; i.e. the transmitted (e.g. broadcasted) SL discovery message may be received by the UE 120. Similarly, step 314 may correspond to step 306 of Figure 3A. In block 316, the UE 120 may utilize the absolute location information for determining location of the UE 120 (e.g. as explained with reference to Figure 2) or it may request the indicated network node to provide the absolute location information in case only the network node is indicated.

One example of utilizing the absolute location information is to determine, by the UE 120, absolute location of the UE 122 and use this information in determining the absolute location of the UE 120 further based on one or more reference signal measurements. Another example may be to provide the absolute location information to another entity, such as the LME 250 or another UE, for determining the absolute location of the UE 120. For example, if the UE 120 is a wrist device or similar, it may provide the absolute location information to a mobile phone for determining location of the UE 120.

Before going into further details, it is now highlighted that there may be at least two different ways to obtain the absolute location information indicating absolute location of the UE 122. First option is that UE 122 directly indicates said information to the UE 120 (and possibly to some other UE(s) as well). The actual indication may be performed in multiple different ways which are discussed below.

Second option is that UE 122 indicates the network node storing the absolute location information. The indication of the network node may be performed in multiple different ways. Third option may be that both the absolute location information (can be abbreviated as ALI) and the network node storing the absolute location information are indicated to the UE 120.

The network node may be indicated e.g. by indicating an identifier (e.g. globally unique identifier) of the network node. For example, the identifier may be transmitted from the UE 122 to the UE 120. In an embodiment, the network node is the UE 122; and thus the UE 122 may indicate itself as the network node storing the ALI. In an embodiment, the network node is an external network node. That is, it may be a network node that is different than the UE 122. For example, the network node may be the LME 250 (e.g. LMF, location server, sensing server, or server UE). In case of server UE indication, in some embodiments the UE 122 itself is the server UE and may thus indicate itself as discussed above.

Instead of transmitting the identifier of the network node storing ALI, the indication maybe an implicit indication. For example, default LMF (LMF located at the core network or server UE) may be indicated. On the other hand, the indication may explicitly indicate the default LMF without necessarily using the identifier of the default LMF. The default LMF may refer to, for example, default or assumed LMF of the UE 120. Thus, if default LMF is indicated, the UE 120 may request the ALI from the LMF that is associated with the UE 120 (e.g. the default LMF of the UE 120).

Let's then draw our attention to Figure 4 illustrating a signalling diagram according to at least one embodiment. In block 400, one or more ciphering keys (CKs) are distributed for UE 122 and UE 120 for enabling ciphered communication for sidelink positioning. Thus, the UE 122 and UE 120 may obtain the one or more CKs. Similarly, if external LME 250 is used in the SL positioning, the LME 250 may also obtain the one or more CKs. Distribution of CK(s) may work, for example, so that different entities involved in the ciphered communication may share their respective CK(s) with other entities. By doing so, the CK(s) may be used to share ciphered information as the information may be deciphered using the CK(s) obtained from the information sharing entity. Thus, for example, the ALI or the indication of the network node may be ciphered by the UE 122 before transmitting the ALI or the indication of the network node. The UE 120 may decipher, using at least one CK of the UE 122, the received information and obtain the ALI or the indication of the network node. However, other UEs or devices may not decipher the information as they may not have the correct CK, and thus the location of the UE 122 may remain secret for said other UEs or devices. This may enhance security of the location sharing. Similar logic may apply also the case(s) in which the network node provisions the ALI to the UE 120. I.e. the ALI may be ciphered and thus may be deciphered by the UE 120 using at least one CK of the network node (e.g. LMF).

Before going into the details of sharing ALI with the UE 120, one example on how to obtain the ALI on the UE 122 may be shown in Figure 4. That is, in block 404 UE 122 may start a positioning session including the LME 250. The positioning session may be Uu based or SL based positioning session in which absolute position of the UE 122 may be obtained. In a further example, the position of the UE 122 may be obtained using a non-RAN specific positioning such as satellite positioning or the like.

In the example of Fig. 4, the LME 250 may obtain absolute location information on the UE 122 (block 406), for example, based on Uu or SL positioning of the UE 122. For example, the SL positioning may be based on mobile-terminated localization request (MT-LR).

In step 408, the LME 250 may provide the absolute location information (i.e. ALl) to the UE 122. Additionally, the LME 250 may request (i.e. explicit request) the UE 122 to start advertising that ALI is available. This request may be sent together with the ALI, for example. For instance, the request may be a flag or bit indicator (e.g. indicateStatusLUE) which requests the UE 122 to activate itself as LUE (located UE). For example, if the value of indicateStatusLUE equals to 1, it may mean that the LME 250 request the UE 122 to start advertising that the ALl is available.

In an embodiment, the UE 122 is configured to obtain, from the network node (e.g. LME 250, the absolute location information on the UE 122 along with a request to indicate, by broadcasting the SL discovery message, that the absolute location information is available. Thus, the UE 122 may start broadcasting the SL discovery message indicating that the location information is available.

In another example, the request to start advertising (i.e. broadcasting the discovery message) is transmitted separately.

In another example, the request to start the advertising is implicit. i.e. by transmitting the ALI to the UE 122, the LME 250 may implicitly request the UE 122 to start the advertising.

In yet another example, the UE 122 may determine to start transmitting the discovery message based on the request from the LME 250 or based on receiving the ALI. In other words, the UE 122 may be activated or activate itself, based on receiving the ALI, as LUE (block 410).

Alternatively, the UE 122 may obtain the absolute location information from another UE of collective localization group.

In block 412, the positioning session may end. However, the UE 122 may then be ready for providing the ALI or indicating the network node storing the ALI for other UEs.

Figure 5A illustrates a signalling diagram according to at least one embodiment. Referring to Figure 5A, in step 502, the UE 122 may transmit SL discovery message indicating that the absolute location of the UE 122 is available. For example, the message may be received by the UE 120 (e.g. target UE 120) In an example embodiment, the SL discovery message comprises a location status information element indicating that the absolute location of the UE 122 is available. The location status information element may be, for example, a flag or a bit indicator. For example, the location status information element may be referred to as statusLUE, wherein value of statusLUE equalling to 1 may indicate that the absolute location of the UE 122 is available. For example, the signalling of step 502 may be transmitted based at least on the absolute location information being available to the UE 122 or being stored at the network node (e.g. at the LME 250).

In an embodiment, the UE 122 is configured to determine whether the absolute location information is available to the UE 122. Based on determining that the absolute location information is available to the UE 122, the UE 122 may transmit the SL discovery message of step 502.

In an embodiment, the UE 122 is configured to determine whether the absolute location information is stored at the network node. Based on determining that the absolute location information is stored the network node, the UE 122 may transmit the SL discovery message of step 502.

In general, the UE 122 may be configured to transmit the SL discovery message indicating that the absolute location information is available based at least on the absolute location information being available to the UE 122 or being stored at the network node.

Determining, by the UE 122, that the absolute location information is available to the UE 122 or is stored at the network node (e.g. the LME 250) may be based on at least one of the following: the absolute location information is stored at the apparatus; the absolute location information is received from the network node; obtaining, by the UE 122 from the network node, an indication that the absolute location information is stored at the network node; or the UE 122 is performing or has performed a localization of the UE 122 with the network node (e.g. as explained with respect to Figure 4).

Considering the first case, the UE 122 may determine that the absolute location information is available to the UE 122 or is stored at the network node based on storing the ALI at the UE 122. Thus, inevitably the absolute location of the UE 122 is available as the ALI indicates the absolute location of the UE 122.

Considering the second case, the UE 122 may determine that the absolute location information is available to the UE 122 or is stored at the network node based on receiving the ALI from the LME 250. For example, the ALI may be received in step 408 of Figure 4 from the LME 250.

Considering the third case, the UE 122 may determine that the absolute location information is available to the UE 122 or is stored at the network node based on receiving an indication from the LME 250 that the ALI is stored at the LME 250.

Fourth case may be that the UE 122 determines that UE's 122 absolute location information is available (i.e. stored) or at least will be available for the LME 250 based on localization of the UE 122, where the localization involves the LME 250. For example, based on performing the positioning session as in Figure 4 with the LME 250, the UE 122 may determine that the absolute location of the UE 122 is known by the LME 250 even if it is not necessarily shared with the UE 122 (as in step 408).

Combination of the different cases may be used by the UE 122 to determine that the absolute location of the UE 122 is available (i.e. ALI stored at the UE 122 or at the network node).

Referring to Figure SA, validity of the ALI may expire as shown in Figure 504. For example, ALI may be considered to be valid for a certain time after which ALI may become invalid. Examples of such timers may be TimeToLive counter or max duration timer that may be reset after every UE 122 localization event. Thus, for example, ALl may be determined to be invalid after certain time has passed from acquiring the ALI (e.g. expiry of a timer that has been started when ALl is obtained). For example, such timer may be started and/or reset (i.e. started from configured value) based on receiving the ALl from the LME 250 (e.g. as in step 408).

In another example, the validity of ALI may expire (i.e. ALl may become invalid, i.e. is no longer valid or considered to be valid) based on mobility event such as acceleration, timing advance change, handover, and/or variation in reference signal, such as reference signal received power (RSRP). For example, the UE 122 may detect the mobility event and based on that determine that the ALI is not valid anymore.

In another example, the validity of ALI may expire based on receiving a message or command from the network node (e.g. LME 250). For example, the LME 250 may indicate that the ALI is no longer valid.

Further, the UE 122 may indicate to the LME 250 if ALI becomes invalid based on e.g. expiry of timer or mobility event detection as described above. Such indication may be performed by transmitting a message, by the UE 122 to the LME, indicating that ALI is not valid. For example, this may enable the LIME 250 to start new positioning session to localize the UE 122 so that it can continue to operate as an anchor UE.

Based on absolute location information being or become invalid, the UE 122 may generate and transmit a discovery message that indicates that location information is not available (step 506). In another embodiment, the UE 122 may simply stop transmitting message of step 502 and not transmit message 506. As discussed herein, the discovery message (e.g. of step 502) may be a 20 SL discovery message that is broadcasted by the UE 122. Thus, said message may be received by one or more UEs, such as by the UE 120. Thus, UE 120 may determine whether or not absolute location of the UE 122 is available.

Figure 5B illustrates an embodiment in which the SL discovery message comprises the absolute location information and/or the indication of the network node storing the absolute location information. The SL discovery message transmitted in step 512 may thus, for example, comprise e.g. the location status information element indicating that the absolute location of the UE 122 is available and additionally the ALI and/or the indication of the network node. Therefore, the SL discovery message itself can be used to convey location information (i.e. ALI or the indication of the network node storing the ALI). This brings the benefit that additional signalling between the UE 122 and UE 120 may not necessarily be needed. However, it may be that UE 120 requests updated ALI or update on the ALI at later stage from the UE 122 (e.g. after a certain time period). Thus, validity of the ALI may be maintained.

In an embodiment, the location information is encrypted using one or more CKs.

For example, the location status information element may be an SLPP metafield that indicates the UE's 122 localized status (e.g., in the form of a raised binary flag). Also, the SLPP field may carry the UE's 122 location information, encrypted with the CK. In this way, other UEs possessing the CK (eg self-localizing target UEs or server UEs) can use the UE 122 as anchor UE for absolute positioning purposes. Once the validity of the LUE location expires (e.g., based on a fixed timer or under UE's 122 mobility), the localized status may be set to reflect the non-LUE status, implying usability only for relative localization (e.g., ranging). See for example step 506 of Figure 5A.

Further it may be beneficial in some examples to provide both the ALI and the indication of the network node to the UE 120 (via the discovery message or via some other signalling/message) as it may enable the UE 120 to quickly obtain the absolute location of the UE 122, but also enable the UE 120 to request the ALI from the indicated network node e.g. after validity of the originally provided ALI expires. I.e. the ALI at the network node may have been updated based on a further or continued positioning session of the UE 122 including the indicated network node (e.g. LME 250).

In an embodiment, the SL discovery message comprises the absolute location information and/or the indication of the network node storing the absolute location information, but not the location status information element.

Thus, the ALI or the indication of the network node in the SL discovery message may implicitly indicate the location status of the UE 122 (i.e. located UE or absolute location of the UE 122 is available).

In an embodiment, the SL discovery message, such as the one in step 512, is transmitted based on (e.g. in response to) a SL discovery message received from the UE 120 (i.e. transmitted by the UE 120). For example, the SL discovery message received from the UE 120 may request indication of location status of the UE 122 (or any other UE receiving said message). Thus, the UE 122 may respond by transmitting the discovery message of step 512. The SL discovery message transmitted by the UE 120 may be referred to herein as SL discovery request for clarity reasons. However, it may be a SL discovery message that is used to request for the location status of the UE 122.

In another embodiment, the SL discovery message, such as the one in step 512, is transmitted without request from the UE 120. For example, the SL discovery message may be transmitted periodically. For example, the periodic transmission may be started based on one or more criteria being met.

For example, the UE 122 may start transmitting the SL discovery message (with or without location information as in Figure 5B) indicating that the absolute location information is available based on at least one of the following: obtaining, from the network node (e.g. LME 520), a request for indicating that the absolute location information is available (see e.g. step 408 of Figure 4); receiving a SL discovery request for indicating whether the absolute location information is available (see e.g. Figure SC step 522); localization of the UE 122 being completed (see e.g. Figure 4 in which UE 122 is positioned); starting to act or determining to start to act as an anchor UE for absolute positioning; or determining that the UE 122 is or is going to serve as an anchor UE for absolute positioning. Any one of the described criteria may alone or in combination with any other one(s) of the criteria be used as a trigger for starting broadcasting the SL discovery message indicating that absolute location is available. So, for example, the UE 122 may be configured to start transmitting the SL discovery message based on both conditions being met request from the LME 250 is received and request from the UE 120 is received. On the other hand, the UE 122 may configured to start transmitting the SL discovery message based on only one of the criterion being met. Additionally, and as explained above, in order to indicate that absolute location is available, the absolute location should be available either directly from the UE 122 or from the network node storing ALI.

In an embodiment, the UE 122 is configured to generate a location information message comprising the absolute location information and/or an indication of the network node storing the absolute location information; and to transmit the location information message to the UE 120. The location information message may be separate to the SL discovery message. For example, the location information message may be ciphered using the one or more CKs. For example, this may mean that the absolute location information and/or an indication of the network node is ciphered.

In an embodiment, the UE 120 is configured to receive the location information message. If the contents are ciphered, the UE 120 may decipher the location information message to obtain the absolute location information and/or an indication of the network node.

In an embodiment, the UE 122 is configured to transmit the location information message based on receiving a location information request for the absolute location information from the UE 120. In an example, the location information message is transmitted in response to receiving the request.

Accordingly, the UE 120 may be configured to generate the location information request for the absolute location information. For example, the location information request may be generated and/or transmitted based on receiving, from the UE 122, SL discovery message indicating that the absolute location information is available (e.g. as in step 502 of Figure 5A). For example, the location information request may be ciphered (or encrypted) using one or more CK(s) shared between the UE 120 and UE 122 (e.g. as in Figure 4). However, the main benefit of ciphering may be to hide the location information (e.g. ALI) from harmful entities and thus other messaging could potentially not be ciphered at all even if the location information is ciphered. However, this may depend on implementation.

Figure 5C illustrates a signalling diagram according to at least one embodiment in which location information is requested and provided to the UE 120 by the UE 122. Referring to Figure SC, in step 522, the UE 120 may request, using SL discovery request, the UE 122 (and possibly other UEs as well) to indicate whether or not absolute location is available. Before transmitting the SL discovery request, the UE 120 may generate the request.

In the example, absolute location of the UE 122 is available and thus UE 122 may respond (e.g. start to transmit) by transmitting SL discovery message indicating that the absolute location information is available (step 524). In this example, the SL discovery message may not comprise the ALI or the indication of the network node storing the ALI.

UE 120 may receive the discovery message transmitted in step 524 and based on the receiving the SL discovery message, request absolute location information on the UE 122 by transmitting the location information request to the UE 122 (step 528). For example, the location information request may be generated and/or transmitted based on receiving, from the UE 122, SL discovery message indicating that the absolute location information is available (e.g. as in step 502 of Figure 5A or as in step 524 of Figure 5C).

The UE 122 may receive the location information request and based on the location information request, transmit the location information message including the ALI and/or the indication of the network node (e.g. identifier of the network node) to the UE 120 (step 530). Thus, the UE 120 may obtain the ALI on the UE 122 or at least may determine the network node from which the ALI may be requested.

In an embodiment, the location information request is a capability request message such as requestCapability message. Accordingly, the location information message may be capability indicating message such as provideCapability. Other ways of delivery are possible, for example via assistance data format and/or via RRC.

In embodiment, the SL discovery message indicating that the absolute location of the UE 122 is available (i.e. absolute location information (abbreviated as ALI) is available) comprises a validity indicator indicating a time period for which the absolute location is valid. For example, the SL discovery message may indicate that the absolute location information is valid for a certain time or time period. Or as discussed above, the SL discovery message may simply comprise a time stamp indicating the time at which the absolute location is obtained. In this case, the time stamp may be understood as validity indicator. Based on such information the UE 120 may determine whether it request the location information from UE 122 e.g. as in step 528. Even expired location information may still be useful for retrospective localization, e.g. as part of a continuous positing tracking process. However, such decisions may be left up to implementation as it may depend on the situation the UE 120 is in.

In an embodiment, Figures 5B and 5C can be understood to illustrate cases in which ALI is stored at the UE 122 and thus can be directly provided to the UE 120 either via the SL discovery message 512 or via location information message 530. Such may be beneficial e.g. in cases in which at least one of the UEs 120, 122 is not connected to the cellular network (e.g. in a tunnel or some network disturbance) or more specifically to the LME 250 (e.g. LMF). Figures 6A and 6B illustrate example embodiments in which the ALI is stored at the network node (i.e. LME 250) and thus the indication of the LME 250 may be provided by the UE 122 to the UE 120.

Referring first to Figure 6A, in step 602, the UE 120 may transmit SL discovery request for absolute location information to the UE 122.

In step 604, the UE 122 may respond by transmitting SL discovery message indicating that the absolute location is available and also including indication of the LME 250. As explained above, one example of such indication is identifier of the LME 250. Another example could be to indicate default LME.

The UE 120 may obtain the indication of the LME storing the absolute location information based on receiving the SL discovery message (step 604).

In step 606, the UE 120 may request the absolute location information from the LME 250. The location information request of step 606 may be generated and/or transmitted based on the SL discovery message 604.

The LME 250 may receive the request and based on the request transmit location information message to the UE 120 (step 608). The UE 120 may receive the location information message. As noted earlier, the location information message may be ciphered at least in some examples. In the case that the location information message is transmitted by the LME 250 it comprises the ALI (and not the indication of the LME 250). Thus, the LME 250 may transmit ALI on the UE 122 to the UE 120 in step 608.

Referring then to Figure 6B, discovery request of step 612 may correspond to discovery request of step 602 of Figure 6A. However, instead of indicating the LME in the discovery message (or discovery response) of step 614, the discovery message may only indicate that the absolute location is available. Therefore, the UE 120 may transmit location information request to the UE 122 in step 616 to request the ALI on the UE 122.

As ALI is stored at the LME 250 and not at the UE 122, the UE may respond by transmitting location information message indicating the LME 250 (step 618). UE 120 may thus determine the network node (i.e. LME 250 in the example) from which it may request the ALI. Step 622 may thus correspond to step 606 of Figure 6A, and step 624 may correspond to step 608 of Figure 6A.

Figure 6C illustrates yet another signalling diagram according to at least one embodiment. Referring to Figure 6C, in step 632, the LME 250 may indicate to the UE 122 to stop providing absolute location information. This may mean that the UE 122 deactivates its status as LUE (step 634). Thus, for example, the UE 122 may stop transmitting the SL discovery message indicating that absolute location is available and/or start transmitting an SL discovery message that indicates that absolute location information is not available.

In general, the UE 122 may be caused to generate an SL discovery message indicating that absolute location information is not available if the absolute location is not available or is not valid; and based on the absolute location information not being available or not being valid, transmitting said another SL discovery message. For example, the UE 122 may determine, based on an expiry of a timer or a message received from the LME 250 (e.g. step 632), that the absolute location information is no longer valid or no longer available; and based on the determining, transmit said SL discovery message indicating that the absolute location information is not available. For example, said SL discovery message may be received by one or more UEs, such by the UE 120.

In the example of Figure 6C, another UE 690 requests location information on the UE 122 from the LME 250 (step 636). However, as the UE 122 has been deactivated as LUE, the LME 250 may provide information on other anchor UE (candidates) for the UE 690. Thus, the UE 690 may request absolute location information on said other anchor UE candidate(s).

Thus, for example, once the LUE 122 is no more needed as an anchor (e.g. all absolute positioning sessions in the area are concluded), the LME 250 may explicitly inform the LUE to stop advertising its LUE status (step 632). If any other UE, e.g. UE 690, requests meanwhile the information of LUE 122 location, this request may be rejected or a "void" answer is provided to indicate the LUE status.

In other embodiment, alternative anchor LUEs with known location status may be provided to the target UE 690 to assist with its positioning.

Figure 7 illustrates at least one embodiment. Referring to Figure 7, actions of the UE 122 may be summarized with respect to transmitting the SL discovery message indicating whether or not absolute location is available.

In step 702, the UE 122 may determine whether absolute location of the UE 122 is known by the UE 122 and is valid. If true, the UE 122 may advertise itself as LUE (i.e. located UE) (block 704) by transmitting e.g. the SL discovery message indicating that absolute location is available.

If not true, the UE 122 may determine (step 712) whether absolute location of the UE 122 is known by some other network node and whether the absolute location is valid. If yes (i.e. valid absolute location is known), the process may continue to block 704.

If not true, the UE 122 may stop advertising itself as located UE, prevent advertising itself as located UE or advertise itself as not located UE which means that the UE 122 may be used for relative positioning, but not for absolute positioning of the UE 120 or some other target UE(s) (block 714).

The process may continue again to block 702 and thus may be performed repetitively, for example.

For example, the UE 120 (although not shown in Figure 7) may receive the SL discovery message indicating that the absolute location information is not available and therefore ask a different UE to support its positioning in the future. An embodiment, as shown in Figure 8, provides an apparatus 10 comprising a control circuitry (CTRL) 12, such as atleast one processor, and at least one memory 14 storing instructions (INSTRUCT.) that, when executed by the at least one processor, cause the apparatus at least to carry out any one of the above-described processes. In an example, the at least one memory and the instructions are configured, with the at least one processor, to cause the apparatus to carry out any one of the above-described processes. The memory may be implemented using any suitable data storage technology, such as semiconductor-based memory devices, flash memory, magnetic memory devices and systems, optical memory devices and systems, fixed memory and removable memory. The memory may comprise a database for storing data.

In an embodiment, the apparatus 10 comprises the terminal device of a communication system, e.g. a user terminal (UT), a computer (PC), a laptop, a tabloid computer, a cellular phone, a mobile phone, a communicator, a smart phone, a palm computer, a mobile transportation apparatus (such as a car), a household appliance, or any other communication apparatus, commonly called as UE in the description. Alternatively, the apparatus is comprised in such a terminal device. Further, the apparatus may be or comprise a module (to be attached to the UE) providing connectivity, such as a plug-in unit, an "USB dongle", or any other kind of unit. The unit may be installed either inside the UE or attached to the UE with a connector or even wirelessly.

In an embodiment, the apparatus 10 is or is comprised in the UE 122. The apparatus may be caused to execute some of the functionalities of the above described processes, such as the steps 302, 304, and 306 of Figure 3A.

The apparatus 10 may further comprise a radio interface (TRX) 16 comprising hardware and/or software for realizing communication connectivity according to one or more communication protocols. The TRX may provide the apparatus with communication capabilities to access the radio access network, for example. For example, the TRX may enable SL communication.

The apparatus may also comprise a user interface 18 comprising, for example, at least one keypad, a microphone, a touch display, a display, a speaker, etc. The user interface may be used to control the apparatus by the user.

In an embodiment, the control circuitry 12 comprises a generating circuitry 20 for performing at least the step 302 of Figure 3A; a transmitting circuitry 22 for performing at least the step 304 of Figure 3A; and an indicating circuitry 24 for performing at least the step 306 of Figure 3A.

An embodiment, as shown in Figure 9, provides an apparatus 50 comprising a control circuitry (CTRL) 52, such as atleast one processor, and at least one memory 54 storing instructions (INSTRUCT.) that, when executed by the at least one processor, cause the apparatus at least to carry out any one of the above-described processes. In an example, the at least one memory and the instructions are configured, with the at least one processor, to cause the apparatus to carry out any one of the above-described processes. The memory may be implemented using any suitable data storage technology, such as semiconductor-based memory devices, flash memory, magnetic memory devices and systems, optical memory devices and systems, fixed memory and removable memory. The memory may comprise a database for storing data.

In an embodiment, the apparatus 50 comprises the terminal device of a communication system, e.g. a user terminal (UT), a computer (PC), a laptop, a tabloid computer, a cellular phone, a mobile phone, a communicator, a smart phone, a palm computer, a mobile transportation apparatus (such as a car), a household appliance, or any other communication apparatus, commonly called as UE in the description. Alternatively, the apparatus is comprised in such a terminal device. Further, the apparatus may be or comprise a module (to be attached to the UE) providing connectivity, such as a plug-in unit, an "USB dongle", or any other kind of unit. The unit may be installed either inside the UE or attached to the UE with a connector or even wirelessly.

In an embodiment, the apparatus 50 is or is comprised in the UE 120. The apparatus may be caused to execute some of the functionalities of the above described processes, such as the steps 312, 314, and 316 of Figure 3B.

The apparatus 50 may further comprise a radio interface (TRX) 56 comprising hardware and/or software for realizing communication connectivity according to one or more communication protocols. The TRX may provide the apparatus with communication capabilities to access the radio access network, for example. For example, the TRX may enable SL communication.

The apparatus 50 may also comprise a user interface 58 comprising, for example, at least one keypad, a microphone, a touch display, a display, a speaker, etc. The user interface may be used to control the apparatus by the user.

In an embodiment, the control circuitry 52 comprises a receiving circuitry 60 for performing at least the step 312 of Figure 3B; an obtaining circuitry 62 for performing at least the step 314 of Figure 3B; and an utilizing circuitry 64 for performing at least the step 316 of Figure 3B.

According to an aspect there is provided an apparatus comprising: at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the apparatus at least to perform: obtaining absolute location information indicating absolute location of a first terminal device (e.g. UE 122); and requesting the first terminal device to transmit, based on the requesting or based on a further request via a second terminal device (e.g. UE 120), SL discovery message indicating that the absolute location information is available. For example, the apparatus may be or be comprised in the LME 250, such as LMF or server UE.

Additionally, the apparatus may be configured to provide the absolute location information to the first terminal device as described above (e.g. in step 408) Additionally, the apparatus may be configured to provide the absolute location information to the second terminal device based on (e.g. upon) request from the second terminal device (e.g. as in steps 606/608 and/or 622/624). In an embodiment, an apparatus carrying out at least some of the embodiments described comprises at least one processor and at least one memory including instructions, that when executed by the at least one processor, cause the apparatus to carry out the functionalities according to any one of the embodiments described. According to an aspect, when the at least one processor executes the instructions, the instructions cause the apparatus to carry out the functionalities according to any one of the embodiments described. According to another embodiment, the apparatus carrying out at least some of the embodiments comprises the at least one processor and at least one memory including instructions, wherein the at least one processor and the instructions perform at least some of the functionalities according to any one of the embodiments described. Accordingly, the at least one processor, the memory, and the instructions form processing means for carrying out at least some of the embodiments described. According to yet another embodiment, the apparatus carrying out at least some of the embodiments comprises a circuitry including at least one processor and at least one memory including instructions. When activated, the circuitry causes the apparatus to perform the at least some of the functionalities according to any one of the embodiments described.

As used in this application, the term 'circuitry' refers to all of the following: (a) hardware-only circuit implementations, such as implementations in only analog and/or digital circuitry, and (b) combinations of circuits and soft-ware (and/or firmware), such as (as applicable): (i) a combination of processor(s) or (ii) portions of processor(s)/software including digital signal processor(s), software, and memory(ies) that work together to cause an apparatus to perform various functions, and (c) circuits, such as a microprocessor(s) or a portion of a microprocessor(s), that require software or firmware for operation, even if the software or firmware is not physically present. This definition of 'circuitry' applies to all uses of this term in this application. As a further example, as used in this application, the term 'circuitry' would also cover an implementation of merely a processor (or multiple processors) or a portion of a processor and its (or their) accompanying software and/or firmware. The term 'circuitry' would also cover, for example and if applicable to the particular element, a baseband integrated circuit or applications processor integrated circuit for a mobile phone or a similar integrated circuit in a server, a cellular network device, or another network device.

In an embodiment, at least some of the processes described may be carried out by an apparatus comprising corresponding means for carrying out at least some of the described processes. Some example means for carrying out the processes may include at least one of the following: detector, processor (including dual-core and multiple-core processors), digital signal processor, controller, receiver, transmitter, encoder, decoder, memory, RAM, ROM, software, firmware, display, user interface, display circuitry, user interface circuitry, user interface software, display software, circuit, antenna, antenna circuitry, and circuitry. A term non-transitory, as used herein, is a limitation of the medium itself (i.e. tangible, not a signal) as opposed to a limitation on data storage persistency (e.g. RAM vs. ROM).

As used herein the term "means" is to be construed in singular form, i.e. referring to a single element, or in plural form, i.e. referring to a combination of single elements. Therefore, terminology "means for [performing A, B, Cy, is to be interpreted to cover an apparatus in which there is only one means for performing A, B and C, or where there are separate means for performing A, B and C, or partially or fully overlapping means for performing A, B, C. Further, terminology "means for performing A, means for performing B, means for performing C" is to be interpreted to cover an apparatus in which there is only one means for performing A, B and C, or where there are separate means for performing A, B and C, or partially or fully overlapping means for performing A, B, C. The techniques and methods described herein may be implemented by various means. For example, these techniques may be implemented in hardware (one or more devices), firmware (one or more devices), software (one or more modules), or combinations thereof. For a hardware implementation, the apparatus(es) of embodiments may be implemented within 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), processors, controllers, micro-controllers, microprocessors, other electronic units designed to perform the functions described herein, or a combination thereof. For firmware or software, the implementation can be carried out through modules of at least one chip set (e.g. procedures, functions, and so on) that perform the functions described herein. The software codes may be stored in a memory unit and executed by processors. The memory unit may be implemented within the processor or externally to the processor. In the latter case, it can be communicatively coupled to the processor via various means, as is known in the art. Additionally, the components of the systems described herein may be rearranged and/or complemented by additional components in order to facilitate the achievements of the various aspects, etc., described with regard thereto, and they are not limited to the precise configurations set forth in the given figures, as will be appreciated by one skilled in the art.

Embodiments as described may also be carried out in the form of a computer process defined by a computer program or portions thereof. Embodiments of the methods described may be carried out by executing at least one portion of a computer program comprising corresponding instructions. The computer program may be in source code form, object code form, or in some intermediate form, and it may be stored in some sort of carrier, which may be any entity or device capable of carrying the program. For example, the computer program may be stored on a computer program distribution medium readable by a computer or a processor. The computer program medium may be, for example but not limited to, a record medium, computer memory, read-only memory, electrical carrier signal, telecommunications signal, and software distribution package, for example. The computer program medium may be a non-transitory medium. Coding of software for carrying out the embodiments as shown and described is well within the scope of a person of ordinary skill in the art.

Examples:

Example 1: An apparatus comprising: at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the apparatus at least to perform: generating a sidelink, SL, discovery message indicating that absolute location information, being indicative of an absolute location of the apparatus, is available; transmitting the SL discovery message at least to a terminal device; and indicating, to the terminal device, at least one of the absolute location information or a network node storing the absolute location information.

Example 2: The apparatus of example 1, wherein the SL discovery message comprises at least one of the absolute location information or an indication of the network node storing the absolute location information.

Example 3: The apparatus of example 1 or 2, wherein the SL discovery message comprises a location status information element indicating that the absolute location of the apparatus is available.

Example 4: The apparatus of any of examples 1 to 3, caused to perform: generating a location information message comprising at least one of the absolute location information or an indication of the network node storing the absolute location information; and transmitting the location information message to the terminal device.

Example 5: The apparatus of example 4, caused to perform: receiving a location information request for the absolute location information, wherein generating the location information message is based on receiving the location information request.

Example 6: The apparatus of any of examples 1 to 5, caused to perform: receiving a SL discovery request for indicating whether the absolute location information is available, wherein transmitting the SL discovery message indicating that the absolute location information is available is based on receiving the SL discovery request.

Example 7: The apparatus of any of examples 1 to 6, wherein the apparatus is caused to transmit the SL discovery message indicating that the absolute location information is available based at least on the absolute location information being available to the apparatus or being stored at the network node. Example 8: The apparatus of example 7, caused to perform: determining that the absolute location information is available to the apparatus or is stored at the network node based on at least one of the following: the absolute location information is stored at the apparatus; the absolute location information is received from the network node; obtaining, from the network node, an indication that the absolute location information is stored at the network node; or the apparatus is performing or has performed a localization of the apparatus with the network node.

Example 9: The apparatus of any of examples 1 to 8, wherein the apparatus is caused to start transmitting the SL discovery message indicating that the absolute location information is available based on at least one of the following: obtaining, from the network node, a request for indicating that the absolute location information is available; receiving a SL discovery request for indicating whether the absolute location information is available; localization of the apparatus being completed; starting to act or determining to start to act as an anchor UE for absolute positioning; or determining that the apparatus is or is going to serve as an anchor UE for absolute positioning.

Example 10: The apparatus of any of examples 1 to 9, caused to perform: obtaining, from the network node, the absolute location information on the apparatus along with a request to indicate, by broadcasting the SL discovery message, that the absolute location information is available.

Example 11: The apparatus of any of examples 1 to 10, wherein the SL discovery message further indicates that the absolute location information is valid for a certain time.

Example 12: The apparatus of any of examples 1 to n, caused to perform: generating another SL discovery message indicating that absolute location information is not available; and based on the absolute location information not being available or not being valid, transmitting said another SL discovery message at least to the terminal device.

Example 13: The apparatus of example 12, caused to perform: determining, based on an expiry of a timer or a message received from the network node, that the absolute location information is no longer valid; and based on the determining, transmitting said another SL discovery message at least to the terminal device.

Example 14: An apparatus comprising: at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the apparatus at least to perform: receiving, from a terminal device, a sidelink, SL, discovery message indicating that absolute location information, being indicative of an absolute location of the terminal device, is available; obtaining, from the terminal device, at least one of the absolute location information or an indication of a network node storing the absolute location information; and utilizing at least one of the absolute location information or the indication of the network node storing the absolute location information for determining a location of the apparatus.

Example 15: The apparatus of example 14, wherein the SL discovery message comprises at least one of the absolute location information or the indication of the network node storing the absolute location information.

Example 16: The apparatus of example 14 or 15, wherein the SL discovery message comprises a location status information element indicating that the absolute location of the terminal device is available.

Example 17: The apparatus of any of examples 14 to 16, caused to perform: receiving, from the terminal device, a location information message comprising at least one of the absolute location information or the indication of the network node storing the absolute location information.

Example 18: The apparatus of any of examples 14 to 17, caused to perform: generating a location information request for the absolute location information based on receiving the SL discovery message indicating that the absolute location information is available; and transmitting the location information request to the terminal device.

Example 19: The apparatus of any of example 14 to 18, caused to perform: generating a SL discovery request for indicating whether absolute location information is available; and transmitting, at least to the terminal device, the generated SL discovery request.

Example 20: The apparatus of any of examples 14 to 19, caused to perform: obtaining, from the terminal device, the indication of the network node storing the absolute location information; requesting the absolute location information from the network node; and receiving the absolute location information from the network node.

Example 21: The apparatus of any of examples 14 to 20, wherein the received SL discovery message further indicates that the absolute location information is valid for a certain time.

Example 22: The apparatus of any of examples 14 to 21, caused to perform: receiving, from the terminal device, another SL discovery message indicating that absolute location information is not available.

Example 23: An apparatus comprising: at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the apparatus at least to perform: obtaining absolute location information indicating absolute location of a first terminal device; and requesting the first terminal device to transmit, based on the requesting or based on a further request via a second terminal device, SL discovery message indicating that the absolute location information is available.

Example 24: A method comprising: generating, by an apparatus, a sidelink, SL, discovery message indicating that absolute location information, being indicative of an absolute location of the apparatus, is available; transmitting the SL discovery message at least to a terminal device; and indicating, to the terminal device, at least one of the absolute location information or a network node storing the absolute location information.

Example 25: A method comprising: receiving, by an apparatus from a terminal device, a sidelink, SL, discovery message indicating that absolute location information, being indicative of an absolute location of the terminal device, is available; obtaining, from the terminal device, at least one of the absolute location information or an indication of a network node storing the absolute location information; and utilizing at least one of the absolute location information or the indication of the network node storing the absolute location information for determining a location of the apparatus.

Example 26: A method comprising: obtaining, by an apparatus, absolute location information indicating absolute location of a first terminal device; and requesting the first terminal device to transmit, based on the requesting or based on a further request via a second terminal device, SL discovery message indicating that the absolute location information is available.

Example 27: A computer program product comprising program instructions which, when loaded into an apparatus, execute the method according to any of examples 24 to 26.

Even though the invention has been described above with reference to an example according to the accompanying drawings, it is clear that the invention is not restricted thereto but can be modified in several ways within the scope of the appended claims. Therefore, all words and expressions should be interpreted broadly and they are intended to illustrate, not to restrict, the embodiment. It will be obvious to a person skilled in the art that, as technology advances, the inventive concept can be implemented in various ways. Further, it is clear to a person skilled in the art that the described embodiments may, but are not required to, be combined with other embodiments in various ways.

Claims

CLAIMS1. An apparatus comprising: at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the apparatus at least to perform: generating a sidelink, SL, discovery message indicating that absolute location information, being indicative of an absolute location of the apparatus, is available; transmitting the SL discovery message at least to a terminal device; and indicating, to the terminal device, at least one of the absolute location information or a network node storing the absolute location information.
2. The apparatus of claim 1, wherein the SL discovery message comprises at least one of the absolute location information or an indication of the network node storing the absolute location information.
3. The apparatus of claim 1 or 2, wherein the SL discovery message comprises a location status information element indicating that the absolute location of the apparatus is available.
4. The apparatus of any preceding claim, caused to perform: generating a location information message comprising at least one of the absolute location information or an indication of the network node storing the absolute location information; and transmitting the location information message to the terminal device.
S. The apparatus of claim 4, caused to perform: receiving a location information request for the absolute location 30 information, wherein generating the location information message is based on receiving the location information request.
6. The apparatus of any preceding claim, caused to perform: receiving a SL discovery request for indicating whether the absolute location information is available, wherein transmitting the SL discovery message indicating that the absolute location information is available is based on receiving the SL discovery request.
7. The apparatus of any preceding claim, wherein the apparatus is caused to transmit the SL discovery message indicating that the absolute location information is available based at least on the absolute location information being available to the apparatus or being stored at the network node.
8. The apparatus of claim 7, caused to perform: determining that the absolute location information is available to the apparatus or is stored at the network node based on at least one of the following: the absolute location information is stored at the apparatus; the absolute location information is received from the network node; obtaining, from the network node, an indication that the absolute location information is stored at the network node; or the apparatus is performing or has performed a localization of the apparatus with the network node.
9. The apparatus of any preceding claim, wherein the apparatus is caused to start transmitting the SL discovery message indicating that the absolute location information is available based on at least one of the following: obtaining, from the network node, a request for indicating that the absolute location information is available; receiving a SL discovery request for indicating whether the absolute location information is available; localization of the apparatus being completed; starting to act or determining to start to act as an anchor UE for absolute positioning; or determining that the apparatus is or is going to serve as an anchor UE for absolute positioning.
10. The apparatus of any preceding claim, caused to perform: obtaining, from the network node, the absolute location information on the apparatus along with a request to indicate, by broadcasting the SL discovery message, that the absolute location information is available.
11. The apparatus of any preceding claim, wherein the SL discovery message further indicates that the absolute location information is valid for a certain time.
12. The apparatus of any preceding claim, caused to perform: generating another SL discovery message indicating that absolute location information is not available; and based on the absolute location information not being available or not being valid, transmitting said another SL discovery message at least to the terminal device.
13. The apparatus of claim 12, caused to perform: determining, based on an expiry of a timer or a message received from the network node, that the absolute location information is no longer valid; and based on the determining, transmitting said another SL discovery message at least to the terminal device.
14. An apparatus comprising: at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the apparatus at least to perform: receiving, from a terminal device, a sidelink, SL, discovery message indicating that absolute location information, being indicative of an absolute location of the terminal device, is available; obtaining, from the terminal device, at least one of the absolute location information or an indication of a network node storing the absolute location information; and utilizing at least one of the absolute location information or the indication of the network node storing the absolute location information for determining a location of the apparatus.
15. The apparatus of claim 14, wherein the SL discovery message comprises at least one of the absolute location information or the indication of the network node storing the absolute location information.
16. The apparatus of claim 14 or 15, wherein the SL discovery message comprises a location status information element indicating that the absolute location of the terminal device is available.
17. The apparatus of any of claims 14 to 16, caused to perform: receiving, from the terminal device, a location information message comprising at least one of the absolute location information or the indication of the network node storing the absolute location information.
18. The apparatus of any of claims 14 to 17, caused to perform: generating a location information request for the absolute location information based on receiving the SL discovery message indicating that the absolute location information is available; and transmitting the location information request to the terminal device.
19. The apparatus of any of claims 14 to 18, caused to perform: generating a SL discovery request for indicating whether absolute location information is available; and transmitting, at least to the terminal device, the generated SL discovery request.
20. The apparatus of any of claims 14 to 19, caused to perform: obtaining, from the terminal device, the indication of the network node storing the absolute location information; requesting the absolute location information from the network node; and receiving the absolute location information from the network node.
21. The apparatus of any of claims 14 to 20, wherein the received SL discovery message further indicates that the absolute location information is valid for a certain time.
22. The apparatus of any of claims 14 to 21, caused to perform: receiving, from the terminal device, another SL discovery message indicating that absolute location information is not available.
23. An apparatus comprising: at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the apparatus at least to perform: obtaining absolute location information indicating absolute location of a first terminal device; and requesting the first terminal device to transmit, based on the requesting or based on a further request via a second terminal device, SL discovery message indicating that the absolute location information is available.
24. A method comprising: generating, by an apparatus, a sidelink, SL, discovery message indicating that absolute location information, being indicative of an absolute location of the apparatus, is available; transmitting the SL discovery message at least to a terminal device; and indicating, to the terminal device, at least one of the absolute location information or a network node storing the absolute location information.
25. A method comprising: receiving, by an apparatus from a terminal device, a sidelink, SL, discovery message indicating that absolute location information, being indicative of an absolute location of the terminal device, is available; obtaining, from the terminal device, at least one of the absolute location information or an indication of a network node storing the absolute location information; and utilizing at least one of the absolute location information or the indication of the network node storing the absolute location information for determining a location of the apparatus.
26. A method comprising: obtaining, by an apparatus, absolute location information indicating absolute location of a first terminal device; and requesting the first terminal device to transmit, based on the requesting or based on a further request via a second terminal device, SL discovery message indicating that the absolute location information is available.
27. A computer program product comprising program instructions which, when loaded into an apparatus, execute the method according to any of claims 24 to 26.