Repeater-assisted localization of user equipment

Abstract

There is provided techniques for repeater-assisted localization of UEs. A method is performed by a network node. The method comprises performing an iterative localization procedure (S104). The network node transmits a triggering signal to the UEs and a current set of repeater configurations to at least one repeater node to be used for the repeater-assisted localization of the UEs (S104-2). The network node receives a current set of localization signals from at least some of the UEs directly and / or via reflection at the at least one repeater node, based on the current set of repeater configurations for the iteration (S104-4). The network node performs a localization of these at least some of the UEs based on the current set of localization signals (S104-6). The network node selects an updated set of repeater configurations to be used in a next iteration (S104-8).

Description

[0001] REPEATER-ASSISTED LOCALIZATION OF USER EQUIPMENT

[0002] TECHNICAL FIELD

[0003] Embodiments presented herein relate to methods, a network node, a repeater node, computer programs, and a computer program product for repeater-assisted localization of user equipment.

[0004] BACKGROUND

[0005] Some wireless communication networks provide localization services in diverse application areas, such as detection, ranging and tracking of vulnerable road users, automated guided vehicles, or unmanned aerial vehicles. Localization can help to improve the position estimation of both active and passive objects. For active objects, whose positions are estimated using cellular signals, localization can be used as a means to make the position estimation more precise, while for passive objects localization can either be the sole available scheme for determining its position, or sensing data can be fused by data provided by other sensors, such as inertial measurement unit (IMU), onboard light detection and ranging (LIDAR) device, etc. The present disclosure is focused on localization of active objects, such as user equipment.

[0006] Depending on the moving directions of the UEs relative to the network nodes as well as the presence of blockages, there may be localization holes where it may not be possible for the network node to accurately detect the speed, position, direction, or even the presence, of the UEs. In such cases, the presence of repeaters provides means for a second view and thereby improve the localization accuracy. However, this assumes that the exact position of each repeater node is known at the network node. Still, with an unknown number of UEs, the network node cannot properly allocate the resources at the beginning of the localization procedure, since the UEs are not known to be active beforehand. The UEs therefore need to access the channel randomly, which leads to possible collisions, or inter-user interference and, thus, the detection and the localization accuracy drops. Without a dedicated resource allocation to the UEs in a repeater-assisted network, there may be no proper configurations for the repeater nodes for proper reflections, or forwarding, of the signals, which affects the usefulness of the repeater nodes for the localization of the UEs. The above issues increase with an increasing number of UEs.

[0007] Hence, there is still a need for accurate localization of an unknown number of UEs in a resourceefficient way via the use of repeater nodes. SUMMARY

[0008] An object of embodiments herein is to provide accurate localization of an unknown number of UEs in a resource-efficient way via the use of one or more repeater nodes.

[0009] According to a first aspect there is presented a method for repeater-assisted localization of UEs. The method is performed by a network node. The method comprises performing an iterative localization procedure. Each iteration of the repeater-assisted localization procedure comprises the network node transmitting a triggering signal to the UEs and a current set of repeater configurations to at least one repeater node to be used for the repeater-assisted localization of the UEs. Each iteration of the repeater-assisted localization procedure comprises the network node receiving a current set of localization signals from at least some of the UEs directly and / or via reflection at the at least one repeater node, based on the current set of repeater configurations for the iteration. Each iteration of the repeater-assisted localization procedure comprises the network node performing a localization of these at least some of the UEs based on the current set of localization signals. Each iteration of the repeater- assisted localization procedure comprises the network node selecting an updated set of repeater configurations to be used in a next iteration. The updated set of repeater configurations is selected based on the localization of these at least some of the UEs as performed based on the current set of localization signals and on the current set of repeater configurations.

[0010] According to a second aspect there is presented a network node for repeater-assisted localization of UEs. The network node comprises processing circuitry. The processing circuitry is configured to cause the network node to perform an iterative localization procedure. The processing circuitry is further configured to cause the network node to in each iteration of the localization procedure transmit a triggering signal to the UEs and a current set of repeater configurations to at least one repeater node to be used for the repeater-assisted localization of the UEs. The processing circuitry is further configured to cause the network node to in each iteration of the localization procedure receive a current set of localization signals from at least some of the UEs directly and / or via reflection at the at least one repeater node, based on the current set of repeater configurations for the iteration. The processing circuitry is further configured to cause the network node to in each iteration of the localization procedure perform a localization of these at least some of the UEs based on the current set of localization signals. The processing circuitry is further configured to cause the network node to in each iteration of the localization procedure select an updated set of repeater configurations to be used in a next iteration. The updated set of repeater configurations is selected based on the localization of these at least some of the UEs as performed based on the current set of localization signals and on the current set of repeater configurations.

[0011] According to a third aspect there is presented a computer program for repeater-assisted localization of UEs. The computer program comprises computer code which, when run on processing circuitry of a network node, causes the network node to perform actions. One action comprises the network node to perform an iterative localization procedure. One action comprises the network node to in each iteration of the localization procedure transmit a triggering signal to the UEs and a current set of repeater configurations to at least one repeater node to be used for the repeater-assisted localization of the UEs. One action comprises the network node to in each iteration of the localization procedure receive a current set of localization signals from at least some of the UEs directly and / or via reflection at the at least one repeater node, based on the current set of repeater configurations for the iteration. One action comprises the network node to in each iteration of the localization procedure perform a localization of these at least some of the UEs based on the current set of localization signals. One action comprises the network node to in each iteration of the localization procedure select an updated set of repeater configurations to be used in a next iteration. The updated set of repeater configurations is selected based on the localization of these at least some of the UEs as performed based on the current set of localization signals and on the current set of repeater configurations.

[0012] According to a fourth aspect there is presented a method for repeater-assisted localization of UEs. The method is performed by a repeater node. The method comprises performing an iterative repeater- assisted localization procedure. Each iteration of the repeater-assisted localization procedure comprises the repeater node receiving a current set of repeater configurations from the network node to be used for reflecting a current set of localization signals. Each iteration of the repeater-assisted localization procedure comprises the repeater node reflecting the current set of localization signals as received from at least some of the UEs towards the network node based on the current set of repeater configurations.

[0013] According to a fifth aspect there is presented a repeater node for repeater-assisted localization of UEs. The repeater node comprises processing circuitry. The processing circuitry is configured to cause the repeater node to perform an iterative repeater-assisted localization procedure. The processing circuitry is further configured to cause the repeater node to in each iteration of the repeater-assisted localization procedure receive a current set of repeater configurations from the network node to be used for reflecting a current set of localization signals. The processing circuitry is further configured to cause the repeater node to in each iteration of the repeater-assisted localization procedure reflect the current set of localization signals as received from at least some of the UEs towards the network node based on the current set of repeater configurations.

[0014] According to a sixth aspect there is presented a computer program for repeater-assisted localization of UEs. The computer program comprises computer code which, when run on processing circuitry of a repeater node, causes the repeater node to perform actions. One action comprises the repeater node to perform an iterative repeater-assisted localization procedure. One action comprises the repeater node to in each iteration of the localization procedure receive a current set of repeater configurations from the network node to be used for reflecting a current set of localization signals. One action comprises the repeater node to in each iteration of the localization procedure reflect the current set of localization signals as received from at least some of the UEs towards the network node based on the current set of repeater configurations.

[0015] According to a seventh aspect there is presented a computer program product comprising a computer program according to at least one of the third aspect and the sixth aspect and a computer readable storage medium on which the computer program is stored. The computer readable storage medium could be a non-transitory computer readable storage medium.

[0016] Advantageously, these aspects enable repeater-assisted detection and localization of an unknown number of UEs.

[0017] Advantageously, these aspects provide a low complexity and low cost scheme where existing infrastructure, in terms of network nodes and repeater nodes, is used for localization and to obtain a better understanding about the general characteristics of the environment. This, in turn, will improve the versatility and quality of the wireless localization and thereby, indirectly, also the communication between the network node and the UEs.

[0018] Particularly, in different iterations and depending on the number and / or location of detected UEs, the network node can configure the repeater nodes for localization actions in a next iteration. This will give the network node the chance to have a better view on the surrounding area and localize the UEs with high accuracy.

[0019] Advantageously, by using the repeater nodes, these aspects reduce the risk of having localization holes, where the network node alone cannot properly localize the UEs. Advantageously, proper resource allocation to the UEs and proper repeater node configuration reduce the collision probability and further improves the accuracy of the localization.

[0020] Other objectives, features and advantages of the enclosed embodiments will be apparent from the following detailed disclosure, from the attached dependent claims as well as from the drawings.

[0021] Generally, all terms used in the claims are to be interpreted according to their ordinary meaning in the technical field, unless explicitly defined otherwise herein. All references to "a / an / the element, apparatus, component, means, module, step, etc." are to be interpreted openly as referring to at least one instance of the element, apparatus, component, means, module, step, etc., unless explicitly stated otherwise. The steps of any method disclosed herein do not have to be performed in the exact order disclosed, unless explicitly stated.

[0022] BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The inventive concept is now described, by way of example, with reference to the accompanying drawings, in which:

[0024] Fig. 1 is a schematic diagram illustrating a communication network according to embodiments;

[0025] Fig. 2 is a schematic illustration of a repeater node implemented as a network-controlled repeater according to an embodiment;

[0026] Fig. 3 is a schematic illustration of a repeater node implemented as a RIS node according to an embodiment;

[0027] Figs. 4, 5, 6 and 7 are flowcharts of methods according to embodiments;

[0028] Fig. 8 is a signaling diagram of a method according to an embodiment;

[0029] Fig. 9 is a schematic diagram showing functional units of a network node according to an embodiment;

[0030] Fig. 10 is a schematic diagram showing functional modules of a network node according to an embodiment;

[0031] Fig. 11 is a schematic diagram showing functional units of a repeater node according to an embodiment;

[0032] Fig. 12 is a schematic diagram showing functional modules of a repeater node according to an embodiment; and Fig. 13 shows one example of a computer program product comprising computer readable means according to an embodiment.

[0033] DETAILED DESCRIPTION

[0034] The inventive concept will now be described more fully hereinafter with reference to the accompanying drawings, in which certain embodiments of the inventive concept are shown. This inventive concept may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided by way of example so that this disclosure will be thorough and complete, and will fully convey the scope of the inventive concept to those skilled in the art. Like numbers refer to like elements throughout the description. Any step or feature illustrated by dashed lines should be regarded as optional.

[0035] As disclosed above, there is still a need for accurate localization of an unknown number of UEs in a resource-efficient way via the use of repeater nodes.

[0036] According to at least some of the herein disclosed embodiments, the network node will be supported by repeater nodes which reflect, or forward, signals between the UEs and the network node with negligible, or at least known, delay and accurate narrow beamforming.

[0037] The embodiments disclosed herein in particular relate to techniques for repeater-assisted localization of UEs. In order to obtain such techniques, there is provided a network node, a method performed by the network node, a computer program product comprising code, for example in the form of a computer program, that when run on processing circuitry of the network node, causes the network node to perform the method. In order to obtain such techniques, there is further provided a repeater node, a method performed by the repeater node, and a computer program product comprising code, for example in the form of a computer program, that when run on processing circuitry of the repeater node, causes the repeater node to perform the method.

[0038] Fig. 1 is a schematic diagram illustrating a communication network 100 where embodiments presented herein can be applied. Although Fig. 1 illustrates an example communication network 100 comprising a single network node 200 and a single repeater node 300. it is understood that the communication network 100 might comprise a plurality of network nodes 200 as well as a plurality or repeater nodes 300. The network node 200 is configured to localize UEs 110a: 10Od by means of assistance from the repeater node 300. In further detail, in different practical scenarios, the network node 200 may need to detect and localize a large but unknown number of UEs 110a: 110d. In such cases, there is a chance for collisions and / or miss-detection, or miss-localization. Such a problem increases with the number of UEs 110a:110d. On the other hand, sensing accuracy is improved by viewing an object, such as a UE, from different directions. Particularly, depending on the UEs’ locations and directions, there may be localization holes where the network node 200 alone may not be able to sense the UEs, such as UEs 110c, 110d in the present example. For instance, if the UEs are moving perpendicular to the network node 200 (i.e., when the Doppler shift of the line-of-sight signal is zero) or when the UE is blocked by a physical object 180, or when the UE has an unresolvable angle-of-arrival with respect to the network node 200, or when the UE has an unresolvable distance to the network node 200, it may be difficult for the network node 200 to detect the UE at all, or the desirable properties, e.g., speed, direction, etc. In such cases, it is useful to perform localization from another direction. Here, the repeater nodes 300 can be used. The repeater node 300 can be considered as an extension of the network node 200, but located in a different position and pointing beams in different directions as compared to the network node 200. That is, the repeater node 300 can be regarded as logically being part of the network node 200 for all management purposes and reflecting the signal with accurate, possibly narrow, beamforming and negligible, or at least known delay. Thus, depending on the repeater node’s capability and architecture, the network node 200 can use the repeater node 300 to have a different view of the UEs and thereby improve the localization quality, and / or even avoiding localization holes. As illustrated by wireless links 120:170, some of the UEs, such as UEs 110a and 110b are able to communicate directly with the network node 200 whereas UEs 110c and 110d are only able to communicate with the network node 200 via the repeater node 300. One reason for this might be that the line-of-sight path between some of the UEs and the network node is blocked by some physical object 180. According to the illustrative example, without the assistance of the repeater node 300, the network node 200 would not be able to localize UEs 110a, 10Od.

[0039] There could be different types of network nodes 200. In some non-limiting examples, the network node 200 is a (radio) access network node, a radio base station, a base transceiver station, a node B, an evolved node B, a GNB, an access point, an access node, an integrated access and backhaul node, or a transmission and reception point.

[0040] There could be different types of repeater nodes. In some non-limiting examples, and as will be disclosed next, the repeater node 300 can be either a network-controlled repeater node or a reconfigurable intelligent surface (RIS) node (in its active or passive format).

[0041] An example where the repeater node 300 is a network-controlled repeater will be disclosed next with reference to Fig. 2. In this example, the functionality of the repeater node is provided in a network- controlled repeater with beamforming capabilities. In this way, the repeater node 300 could be considered as a network-controlled beam bender when compared to a proper network node, such as a gNB. As such, the network-controlled repeater is logically part of the network node for all management purposes. In this way the network-controlled repeater can be deployed and be under the control of the same mobile network operator as the mobile network operator of the network node 200. In some aspects, the network-controlled repeater is based on an amplify-and-forward relaying scheme. In other words, the network-controlled repeater with the herein disclosed functionality can be regarded as an enhancement over conventional radio-frequency repeaters with the capability to receive and process side control information from the network node as well as performing accurate beamforming. Side control information could allow the network-controlled repeater to perform an amplify-and-forward operation of a sensing signal in a more efficient manner with narrow beams. As illustrated in Fig. 2, the repeater node 300, when being implemented as a network-controlled repeater, is configured to maintain a control link 250 to the network node 200 for receiving configuration from the network node 200 and for providing reports to the network node 200. As further illustrated, a localization signal as transmitted by the UE 110b can be received over an access link 150 and forwarded to the network node 200 over a backhaul link 140. For this purpose, the repeater node 300 might implement a network-controlled repeater mobile termination (NCR-MT) interface for signalling over the control link 250 and a network- controlled repeater forwarding (NCR-FW) interface for signalling over the backhaul link 140 and the access link 150. Operational behavior of the NCR-FW interface might be configured according to information, configurations, or settings as received over the NCR-MT interface from the network node 200.

[0042] An example where the repeater node 300 is a RIS node will be disclosed next with reference to Fig. 3. In general terms, a RIS node is capable of intelligently manipulating the propagation of electro-magnetic waves. The RIS is composed of a 2-dimensional array 370 of reflecting elements 360, where each element acts as a passive reconfigurable scatterer, i.e., a piece of manufactured material, which can be programmed to change an impinging electro-magnetic wave in a customizable way. Such elements are usually low-cost passive surfaces that do not require dedicated power sources, and the radio waves (as here represented by signals on the links 140, 150) impinged upon them can be reflected without the need of employing power amplifier or radio-frequency chain. Moreover, a RIS node can, potentially, operate in full duplex mode without significant self-interference or increased noise level and require only low-rate control link or backhaul connections. The RIS node comprises a controller 350 that is configured to change the settings of the elements 360 to thereby change how an impinging electromagnetic wave is reflected (in terms of direction, beamforming, etc.). In this respect, the controller 350 receives information, configurations, or settings from the network node 200 over a control link 250. A RIS node can be flexibly deployed due to its low weight and low power consumption. A RIS node can be regarded as a network-controlled repeater but with no, or even negative, amplification. That is, the RIS node might be capable of signal reflection via adapting a phase matrix for tuning the elements 360 whilst the network-controlled repeater is capable also of power amplification. Further, because the RIS node only reflects incoming signals, it might have lower internal, or processing, delay, than the network- controlled repeater.

[0043] Reference is now made to Fig. 4 illustrating a method for repeater-assisted localization of UEs 110a:110d as performed by the network node 200 according to an embodiment. The network node 200 does not know a priori for how many UEs 110:110d the repeater-assisted localization is to be performed. Therefore, in some aspects, the repeater-assisted localization is performed for an unknown (from the perspective of the network node 200) number of UEs 110a: 110d.

[0044] S104: The network node 200 performs an iterative localization procedure. A number of steps as disclosed next are performed by the network node 200 during each iteration of the localization procedure.

[0045] S104-2: The network node 200 transmits a triggering signal to the UEs 110a: 110d and a current set of repeater configurations to at least one repeater node 300 to be used for the repeater-assisted localization of the UEs 110a:110d.

[0046] S104-4: The network node 200 receives a current set of localization signals from at least some of the UEs 110a: 110d directly and / or via reflection at the at least one repeater node 300, based on the current set of repeater configurations for the iteration.

[0047] S104-6: The network node 200 performs a localization of these at least some of the UEs 110a: 110d based on the received current set of localization signals. In general terms, the localization involves at least one of detecting the speed, the position, the direction, or even the presence, of the UEs 110a: 110d from which the current set of localization signals was received.

[0048] S104-8: The network node 200 selects an updated set of repeater configurations to be used in a next iteration. The updated set of repeater configurations is selected based on the localization of said at least some of the UEs 110a: 110d as performed based on the current set of localization signals and on the current set of repeater configurations. Step S104-2 can then be entered again for the next iteration of the localization procedure.

[0049] Thus, one occurrence of steps S104-2 to S104-8 are performed during each iteration of the localization procedure. That is, when step S104-8 has been performed for a current iteration of the localization procedure, step S104-2 is entered again for a next iteration of the localization procedure. In other words, the updated set of repeater configurations as selected in step S104-8 is used in step S104-2 of the next iteration of the localization procedure.

[0050] Embodiments relating to further details of repeater-assisted localization of UEs 110a: 110d as performed by the network node 200 will now be disclosed with continued reference to Fig. 4.

[0051] In some aspects, the localization procedure is continued until a stopping criterion is reached. In some examples, the stopping criterion is reached when the localization procedure has been ongoing for a certain period of time. That is, one stopping criterion can be based on expiration of a timer. In some examples, the stopping criterion is reached when a predetermined number of UEs 110a: 110d has been localized. That is, one stopping criterion can be a counting criterion. In some examples, the stopping criterion is reached when less than a certain number of new UEs 110a: 110d have been localized from one iteration to the next. That is, one stopping criterion can be a localization criterion.

[0052] In some aspects, the network node 200 selects the set of repeater configurations in accordance with the capability of the at least one repeater node’s 300 capability to participate in the repeater-assisted localization of the UEs 110a:110d. Therefore, in some embodiments, the network node 200 is configured to perform (optional) step S102.

[0053] S102: The network node 200 receives a capability report about the at least one repeater node 300. The capability report pertains to a capability of the at least one repeater node 300 to participate in the repeater-assisted localization of the UEs 110a:110d. The network node 200 can then select the set of repeater configurations in accordance with the capability report.

[0054] One capability report might be received from each of the repeater nodes 300. Alternatively, one or more capability reports are received from an operations, administration, and management (0AM) node (which could be either an 0AM node of the network node 200 or an 0AM node of the at least one repeater node 300), or from another network node.

[0055] In general term, the capability report conveys information about the repeater node’s 300 ability to form beams with desired characteristics (e.g., beamwidth, main lobe(s), side lobes, etc.), which dictates the beam sweep strategy that the network node 200 may employ utilizing the repeater node 300. The beam sweep strategy might, e.g., relate to the number of required beams for the considered geometry and application. The capability report might indicate the switching delay between beam configurations for the repeater node 300. Since the repeater node 300 needs to be synchronized with the UE transmissions, the switching delay should be taken into account as the network node 200 orchestrates the signaling strategy in the time-domain. In addition, the polarization of the repeater node 300 can be part of the capability report and may be utilized to separate differently polarized signals coming from different links, i.e., directly or via the repeater node 300, or to increase the diversity during the localization process.

[0056] Information about the repeater node’s 300 numbers of beams and beam types (for instance, the repeater node 300 may support few wide beams or a couple of narrow beams) can be used by the network node 200 to configure different beams in different time slots.

[0057] Information about the repeater node’s 300 internal delay can be used by the network node 200 to remove its effect from the end-to-end delay and then find the distance to the UE. Information about the repeater node’s 300 location can by the network node 200 be used for the localization of the UE. Information about the repeater node’s 300 power amplification and gain can be used by the network node 200 for location of the received signal.

[0058] Information about the repeater node’s 300 beam constellation (in the x-y domain), can by the network node 200 be used to configure the repeater node 300 with proper beam indices to be used in different time slots.

[0059] Further details of the content of the capability report will be disclosed below with reference to methods performed by the repeater node 300.

[0060] Further aspects of the triggering signal will be disclosed next.

[0061] In general terms, the triggering signal for the first iteration indicates that the localization procedure starts and the UEs 110a:110d are to transmit localization signals for the network node 200 to localize the UEs 110a:110d. Transmission of such a triggering signal enables the network node 200 to employ a synchronized detection strategy.

[0062] In some aspects, the triggering signal for the first iteration indicates at which time resources the UEs 110a:110d should start transmitting localization signals in random time / frequency resource blocks (among a predefined set of time / frequency resource blocks). In particular, in some embodiments, the triggering signal for the first iteration indicates a set of time resources in which the UEs 110a: 110d are to transmit a first set of localization signals. The time resources can have a granularity of symbol-level, slot-level, frame-level or be indicated with specific time duration.

[0063] In some aspects, the triggering signal for the second iteration is more specific in terms of the specific time / frequency resource blocks to be used by each UE 110a: 110d that was localized in the first iteration, thereby reducing the risk of collisions. In particular, in some embodiments, the triggering signal for the second iteration indicates a set of time and frequency resources in which the UEs 110a: 110d are to transmit a second set of localization signals. The time resources are indicated per UE for the UEs 110a: 110d localized in the first iteration. Here, the time resource(s) to be used for localization may be represented by their starting / ending point, periodicity, duration, etc. The time resources can have a granularity of symbol-level, slot-level, frame-level or be indicated with specific time duration.

[0064] However, whilst the already detected UEs send their localization signals in the specific resource blocks, a sweeping and random resource allocation may still be performed by the network node 200 for a few resource blocks, to thereby increase the chances that not-yet localized UEs 110a: 110d are detected. That is, in some embodiments, the time resources are not indicated per UE for UEs 110a:110d not localized in the first iteration.

[0065] Further aspects of the set of repeater configurations will be disclosed next.

[0066] In general terms, the set of configurations are to be used by the at least one repeater node 300 during the localization procedure. In this way, the network node 200 can synchronize, or configure, all the repeater nodes 300 properly in each iteration of the localization procedure. In some aspects, the set of configurations to be used by the repeater nodes 300 during a first iteration of the localization procedure indicates which beam configurations and / or polarization should be used by the repeater nodes at the time resources associated with the time resources to be used by the UEs 110a: 110d during the first iteration. That is, in some embodiments, the set of repeater configurations for the first iteration indicates time resources and beam configurations and / or polarizations to be used by each at least one repeater node 300 in the time resources.

[0067] Further, in some aspects, the set of repeater configurations for the first iteration comprises instructions for the repeater nodes to use beamforming when reflecting the localization signals. That is, in some embodiments, the set of repeater configurations for the first iteration indicates a beam sweep to be made by the at least one repeater node 300 in the time resources. Here, the repeater nodes may sweep over a number of, possibly, wide beams. Further, the beam configurations for the second iteration might comprise narrower beam widths than the beam configurations for the first iteration.

[0068] As disclosed above, based on the localization made in S104-6, the network node 200 in step S104-8 selects an updated set of repeater configurations to be used in a next iteration. In other words, the set of repeater configurations to be used in the second iteration is based on the localization made in the first iteration. In some aspects, the set of configurations to be used for the second iteration indicate the time / frequency resources, the polarization as well as the beams to be used by the repeater node(s) for the second iteration. That is, in some embodiments, the set of repeater configurations for the second iteration indicates time resources and beam configurations to be used in the time resources, and in some embodiments, the set of repeater configurations for the second iteration indicates time resources and which polarization to be used by each at least one repeater node 300 in which of the time resources. The beam configurations specify which beam to be used by each at least one repeater node 300 in each of the time resources. In some examples, the beam configuration comprises one, or a combination of, narrow and wide beams where, depending on the UEs rough locations as estimated for a current iteration, a specific beam may be used at a certain time in the next iteration. Also, in some examples, the beam configurations are indicated via logical beam indices. The set of configurations might be semi-persistent, semi-static and / or dynamic, and can by the network node 200 be indicated to the at least one repeater node 300 using radio resource control (RRC) signaling, medium access control control element (MAC-CE) signaling, and / or downlink control information (DCI) signaling.

[0069] Further aspects of the localization signals will be disclosed next.

[0070] In some examples, the localization signals are uplink sounding reference signals (SRSs) for positioning. The SRS for positioning is a reference signal based on the SRS for communication. The SRS for positioning can be configured in a resource, which in turn can be part of a resource set. a resource correspond to an SRS beam, and resource sets correspond to a collection of SRS resource (i.e. beams) aimed at a given network node. The SRS resource can be defined as a collection of symbols transmitted on the time-frequency grid, such as on the new radio (NR) time-frequency grid. The SRS resources for positioning might be transmitted on a single antenna port, and can be placed to begin on any symbol in the uplink slot. In the time domain, the SRS resources for positioning might span 1 , 2, 4, 8, or 12 consecutive orthogonal frequency-division multiplexing (OFDM) symbols, which provide enough coverage to reach the network node 200 (directly or via reflection at the one or more repeater nodes 300. In general terms, the localization signals for different UEs should be orthogonal. Further, the localization signals good auto-correlation properties, low complexity, etc. For example, the localization signals could be provided as pilot sequences based on Zadoff-Chu (ZC) sequences or other known patterns in the time domain. In particular, in some embodiments, the localization signals are composed of pilot signals, where each pilot signal comprises an indicator identifying the UE having transmitted the pilot signal. In other case, if a given UE that has not yet interacted with the network node 200 wishes to be detected, or localized, and a random pilot is used from a pool of available pilots, by this given UE then there is not any known identifier for this given UE. In some examples, the number of pilot transmissions relates to different number of beams / configurations that the repeater nodes require to sweep the region, i.e., one transmission for each repeater configuration. In general terms, there are thus as many repeater configurations as there are pilot signals. One respective repeater configuration is to be used per each pilot signals. Therefore in some embodiments, the triggering signal indicates how many pilot signals to be transmitted by each of the UEs 110a: 110d.

[0071] The number of pilot signals as transmitted by each UE per iteration might be set by the network node 200 and indicated in the triggering signal for each iteration. In this respect, the triggering signal might be received with a different delay for each of the UEs, depending on their position 110a: 110d relative the network node 200. Therefore, there will be asynchronous transmissions of pilot signals from the UEs 110a: 110d. The delay spread can be accounted for with the use of a cyclic prefix.

[0072] In general terms, during each iteration of the localization procedure the network node 200 makes certain decisions that impacts the continuation of the localization procedure. For example, the network node 200 performs a localization based on the set of localization signals received from the UEs for the current iteration and makes certain decisions regarding resource allocation, UE trajectory formation, repeater configurations, etc. for the next iteration. That is, in some embodiments, performing the localization of at least some of the UEs 110a: 110d comprises estimating a respective location and / or trajectory for each of these UEs 110a:110d.

[0073] In some embodiments, the localization of at least some of the UEs 110a:110d for the current iteration is a refined localization of at least some of the UEs 110a: 110d for a previous iteration. In further detail, in some examples, a first iteration is performed for localizing a first group of the UEs 110a: 110d, and a second iteration, subsequent to the first iteration, is performed for localizing a second group of the UEs 110a:110d. The second group of UEs 110a: 110d might then be an extension of the first group of UEs 110a:110d. That is, the second group of UEs 110a: 11 Od might include all UEs of the first group of UEs 110a: 110d as well as additional UEs localized during the second iteration. In other words, the first group of UEs 110a: 110d is a (true) subset of the second group of UEs 110a: 110d. There can be different ways for the network node 200 to perform the localization in step S104-6. In this respect, the localization can be performed using any, or any combination, of the Multiple Signal Classification (MUSIC) algorithm, angle of arrival (AoA) estimation, angle of departure (AoD) estimation, range estimation, Doppler frequency detection, received energy per beam estimation, etc. Further in this respect, different localization techniques can be used in the different iterations. This is since the advantages of different localizations techniques vary and there are different factors that may come into play, such as the inclusion of repeater nodes, the actual considered geometry and the available resources (e.g., bandwidth and time) are some of these factors.

[0074] Reference is now made to Fig. 5 illustrating a method for repeater-assisted localization of UEs 110a:110d as performed by the repeater node 300 according to an embodiment.

[0075] S204: The repeater node 300 performs an iterative repeater-assisted localization procedure.

[0076] A number of steps as disclosed next are performed by the repeater node 300 during each iteration of the repeater-assisted localization procedure.

[0077] S204-4: The repeater node 300 receives a current set of repeater configurations from the network node 200 to be used for reflecting a current set of localization signals.

[0078] S204-6: The repeater node 300 reflects the current set of localization signals as received from at least some of the UEs 110a: 110d towards the network node 200 based on the current set of repeater configurations.

[0079] Step S204-4 can then be entered again for the next iteration of the localization procedure.

[0080] Thus, one occurrence of steps S204-4 to S204-6 are performed during each iteration of the localization procedure. That is, when step S204-6 has been performed for a current iteration of the localization procedure, step S204-4 is entered again for a next iteration of the localization procedure.

[0081] Embodiments relating to further details of repeater-assisted localization of UEs 110a: 110d as performed by the repeater node 300 will now be disclosed with continued reference to Fig. 5.

[0082] As disclosed above, the network node 200 might select the set of repeater configurations in accordance with a capability report. In some embodiments, the capability report is transmitted by the repeater node 300 itself. Therefore, in some embodiments, the repeater node 300 is configured to perform (optional) step S202. S202: The repeater node 300 transmits a capability report to the network node 200 pertaining to a capability of the repeater node 300 to participate in the repeater-assisted localization of the UEs 110a:110d.

[0083] In some non-limiting examples, the capability of the repeater node 300 relates to at least one of: beamforming capabilities of the repeater node 300, switching delay between different beams at the repeater node 300, switching delay between uplink and downlink at the repeater node 300, polarization properties of the repeater node 300, and support of single- or dual-directional localization.

[0084] In further non-limiting examples, the capability report might comprise information about one or more of: function as a repeater, beam arrangement report, repeater-Fwd’s reliance on repeater-MT, on / off capability, latency requirements for dynamic indication, switching delay, power allocation capability, number of types (wide / narrow) beams, isolation between transmit and receiver antennas used for sensing, and localization capabilities.

[0085] In further non-limiting examples, the localization capability might comprise information about one or more of: indication of repeater supporting localization, support of single, dual or alternating polarization at the transmit and receive antenna of the repeater access-side used for localization, downlink / uplink switching delay and accuracy for localization, and support of single- or dual-directional localization.

[0086] In some, the capability report is sent via RRC signaling or MAC-CE signaling.

[0087] As disclosed above, the network node 200 in step S104-2 transmits a triggering signal to the UEs 110a: 110d. It might be so that the triggering signal is reflected by the repeater node 300.

[0088] Therefore, in some embodiments, the repeater node 300 is configured to perform (optional) step S204-2 during each iteration of the repeater-assisted localization procedure.

[0089] S204-2: The repeater node 300 reflects a triggering signal as received from the network node 200 towards the UEs 110a:110d.

[0090] However, in other embodiments, the repeater node 300 is at least not explicitly configured to reflect the triggering signal.

[0091] Further aspects of the set of repeater configurations will be disclosed next. In general terms, all aspects, embodiments, and examples as disclosed above with reference to the network node 200 apply also to the repeater node 300. As disclosed above, in some embodiments, the set of repeater configurations for the first iteration indicates time resources and beam configurations and / or polarizations to be used by the repeater node 300 in the time resources.

[0092] As disclosed above, in some embodiments, the set of repeater configurations for the first iteration indicates a beam sweep to be made by the repeater node 300 in the time resources.

[0093] As disclosed above, in some embodiments, the set of repeater configurations for the second iteration indicates time resources and beam configurations to be used in the time resources. The beam configurations specify which beam to be used by the repeater node 300 in each of the time resources.

[0094] As disclosed above, in some embodiments, the set of repeater configurations for a second iteration indicates time resources and which polarization to be used by the repeater node 300 in each of the time resources.

[0095] One particular embodiment for repeater-assisted localization of UEs 110a: 110d as performed by the network node 200 and the repeater node 300 based on at least some of the above disclosed embodiments will now be disclosed in detail with reference to the flowcharts of Fig. 6 and Fig. 7, as well as to the signaling diagram of Fig. 8.

[0096] S30a, S401 , S501 : The repeater node 300 transmits a capability report to the network node 200 pertaining to a capability of the repeater node 300 to participate in the repeater-assisted localization of the UEs 110a:110d.

[0097] 5302, S502: The network node 200 selects a set of repeater configurations to be used by the repeater node 300 in the first iteration of the localization procedure. The set of repeater configurations is selected based on the received capability report.

[0098] 5303, S402, S503: The network node 200 transmits the set of repeater configurations to the repeater node 300 to be used by the repeater node 300 for the first iteration of the repeater-assisted localization of the UEs 110a:110d.

[0099] 5304, S504: The network node 200 transmits a first triggering signal to the UEs 110a: 110d.

[0100] 5305, S404, S505a, S505b: At least some of the UEs 110a:110d transmit localization signals. As disclosed above, the localization signals might be defined by a known number of pilot signals in random resource blocks. Some of the localization signals are reflected by the repeater node 300. The repeater node 300 follows the set of repeater configurations when reflecting the localization signals.

[0101] S306, S506: The network node 200 performs a localization of the UEs 110a: 110d from which the localization signals were received. Here, since the UEs 110a: 110d for the first iteration do not have individually allocated resource blocks and the repeater node 300 does not follow any specific configurations associated with a particular UE, there is a chance for collisions or miss-detections at the network node 200.

[0102] 5302, S507: The network node 200 selecting an updated set of repeater configurations to be used in the second iteration. The updated set of repeater configurations is selected based on the localization of the UEs 110a: 110d in the first iteration and on the set of repeater configurations used by the repeater node 300 in the first iteration.

[0103] 5303, S402, S508: The network node 200 transmits the updated set of repeater configurations to the repeater node 300 to be used by the repeater node 300 for the second iteration of the repeater-assisted localization of the UEs 110a:110d.

[0104] 5304, S509: The network node 200 transmits a second triggering signal to the UEs 110a: 110d.

[0105] 5305, S404, S510a, S510b: At least some of the UEs 110a:110d transmit localization signals. Some of the localization signals are reflected by the repeater node 300.

[0106] 5306, S511 : The network node 200 performs a localization of the UEs 110a: 110d from which the localization signals were received.

[0107] Here, since the UEs 110a: 110d that were successfully located in the first iteration might have individually allocated resource blocks for the second iteration and the repeater node 300 therefore can be configured to follow specific configurations associated with these already localized UEs, the chance for collisions or miss-detections at the network node 200 is significantly reduced compared to the first iteration. In this way, via the repeater node 300, the network node 200 can accurately localize an unknown number of UEs 110a: 110d with low collision probability and at the same time avoid localization holes.

[0108] The method can then, if the stopping criterion has not been reached, continue with the network node 200 selecting an updated set of repeater configurations to be used in the third iteration, as in steps S302, S507, and so on. Fig. 9 schematically illustrates, in terms of a number of functional units, the components of a network node 200 according to an embodiment. Processing circuitry 210 is provided using any combination of one or more of a suitable central processing unit (CPU), multiprocessor, microcontroller, digital signal processor (DSP), etc., capable of executing software instructions stored in a computer program product 1310a (as in Fig. 13), e.g. in the form of a storage medium 230. The processing circuitry 210 may further be provided as at least one application specific integrated circuit (ASIC), or field programmable gate array (FPGA).

[0109] Particularly, the processing circuitry 210 is configured to cause the network node 200 to perform a set of operations, or steps, as disclosed above. For example, the storage medium 230 may store the set of operations, and the processing circuitry 210 may be configured to retrieve the set of operations from the storage medium 230 to cause the network node 200 to perform the set of operations. The set of operations may be provided as a set of executable instructions. Thus the processing circuitry 210 is thereby arranged to execute methods as herein disclosed.

[0110] The storage medium 230 may also comprise persistent storage, which, for example, can be any single one or combination of magnetic memory, optical memory, solid state memory or even remotely mounted memory.

[0111] The network node 200 may further comprise a communications (comm.) interface 220 for communications with other entities, functions, nodes, and devices, as in Fig. 1 , for performing repeater- assisted localization of UEs 110a: 110d according to the herein disclosed embodiments. As such the communications interface 220 may comprise one or more transmitters and receivers, comprising analogue and digital components.

[0112] The processing circuitry 210 controls the general operation of the network node 200 e.g. by sending data and control signals to the communications interface 220 and the storage medium 230, by receiving data and reports from the communications interface 220, and by retrieving data and instructions from the storage medium 230. Other components, as well as the related functionality, of the network node 200 are omitted in order not to obscure the concepts presented herein.

[0113] Fig. 10 schematically illustrates, in terms of a number of functional modules, the components of a network node 200 according to an embodiment. The network node 200 of Fig. 10 comprises a number of functional modules; a localization module 210b configured to perform step S104, a transmit module 210c configured to perform step S104-2, a receive module 21 Od configured to perform step S104-4, a localization module 21 Oe configured to perform step S104-6, and a select module 21 Of configured to perform step S104-8. The network node 200 of Fig. 10 may further comprise a number of optional functional modules, such as a receive module 210a configured to perform step S102. In general terms, each functional module 210a:21 Of may be implemented in hardware or in software. Preferably, one or more or all functional modules 210a:21 Of may be implemented by the processing circuitry 210, possibly in cooperation with the communications interface 220 and / or the storage medium 230. The processing circuitry 210 may thus be arranged to from the storage medium 230 fetch instructions as provided by a functional module 210a:21 Of and to execute these instructions, thereby performing any steps of the network node 200 as disclosed herein.

[0114] Some (radio) access network architectures define network nodes (or gNBs) comprising multiple component parts or nodes: a central unit (CU), one or more distributed units (DUs), and one or more radio units (RUs). The protocol layer stack of the network node is divided between the CU, the DUs and the RUs, with one or more lower layers of the stack implemented in the RUs, and one or more higher layers of the stack implemented in the CU and / or DUs. The CU is coupled to the DUs via a fronthaul higher layer split (HLS) network; the CU / DUs are connected to the RUs via a fronthaul lower-layer split (LLS) network. The DU may be combined with the CU in some embodiments, where a combined DU / CU may be referred to as a CU or simply a baseband unit. A communication link for communication of user data messages or packets between the RU and the baseband unit, CU, or DU is referred to as a fronthaul network or interface. Messages or packets may be transmitted from the network node 200 in the downlink (i.e., from the CU to the RU) or received by the network node 200 in the uplink (i.e., from the RU to the CU).

[0115] The network node 200 may be provided as a standalone device or as a part of at least one further device. For example, the network node 200 may be provided in a node of the radio access network or in a node of the core network. Alternatively, functionality of the network node 200 may be distributed between at least two devices, or nodes. These at least two nodes, or devices, may either be part of the same network part (such as the radio access network or the core network) or may be spread between at least two such network parts. In general terms, instructions that are required to be performed in real time may be performed in a device, or node, operatively closer to the cell than instructions that are not required to be performed in real time. A first portion of the instructions performed by the network node 200 may be executed in a first device, and a second portion of the instructions performed by the network node 200 may be executed in a second device; the herein disclosed embodiments are not limited to any particular number of devices on which the instructions performed by the network node 200 may be executed. Hence, the methods according to the herein disclosed embodiments are suitable to be performed by a network node 200 residing in a cloud computational environment. Therefore, although a single processing circuitry 210, 310 is illustrated in Fig. 9 the processing circuitry 210 may be distributed among a plurality of devices, or nodes. The same applies to the functional modules 21 Oa: 210f of Fig. 10 and the computer program 1320a of Fig. 13.

[0116] Fig. 11 schematically illustrates, in terms of a number of functional units, the components of a repeater node 300 according to an embodiment. Processing circuitry 310 is provided using any combination of one or more of a suitable central processing unit (CPU), multiprocessor, microcontroller, digital signal processor (DSP), etc., capable of executing software instructions stored in a computer program product 1310b (as in Fig. 13), e.g. in the form of a storage medium 330. The processing circuitry 310 may further be provided as at least one application specific integrated circuit (ASIC), or field programmable gate array (FPGA).

[0117] Particularly, the processing circuitry 310 is configured to cause the repeater node 300 to perform a set of operations, or steps, as disclosed above. For example, the storage medium 330 may store the set of operations, and the processing circuitry 310 may be configured to retrieve the set of operations from the storage medium 330 to cause the repeater node 300 to perform the set of operations. The set of operations may be provided as a set of executable instructions. Thus the processing circuitry 310 is thereby arranged to execute methods as herein disclosed.

[0118] The storage medium 330 may also comprise persistent storage, which, for example, can be any single one or combination of magnetic memory, optical memory, solid state memory or even remotely mounted memory.

[0119] The repeater node 300 may further comprise a communications interface 320 for communications with other entities, functions, nodes, and devices, as in Fig. 1 , for performing repeater-assisted localization of UEs 110a: 110d according to the herein disclosed embodiments. As such the communications interface 320 may comprise one or more transmitters and receivers, comprising analogue and digital components.

[0120] The processing circuitry 310 controls the general operation of the repeater node 300 e.g. by sending data and control signals to the communications interface 320 and the storage medium 330, by receiving data and reports from the communications interface 320, and by retrieving data and instructions from the storage medium 330. Other components, as well as the related functionality, of the repeater node 300 are omitted in order not to obscure the concepts presented herein. Fig. 12 schematically illustrates, in terms of a number of functional modules, the components of a repeater node 300 according to an embodiment. The repeater node 300 of Fig. 12 comprises a number of functional modules; a localization module 310b configured to perform step S204, a receive module 31 Od configured to perform step S204-4, and a reflect module 31 Oe configured to perform step S204-6. The repeater node 300 of Fig. 12 may further comprise a number of optional functional modules, such as any of a transmit module 310a configured to perform step S202, and a reflect module 310c configured to perform step S204-2. In general terms, each functional module 310a:31 Oe may be implemented in hardware or in software. Preferably, one or more or all functional modules 310a:31 Oe may be implemented by the processing circuitry 310, possibly in cooperation with the communications interface 320 and / or the storage medium 330. The processing circuitry 310 may thus be arranged to from the storage medium 330 fetch instructions as provided by a functional module 310a:31 Oe and to execute these instructions, thereby performing any steps of the repeater node 300 as disclosed herein.

[0121] Fig. 13 shows one example of a computer program product 1310a, 1310b comprising computer readable means 1330. On this computer readable means 1330, a computer program 1320a can be stored, which computer program 1320a can cause the processing circuitry 210 and thereto operatively coupled entities and devices, such as the communications interface 220 and the storage medium 230, to execute methods according to embodiments described herein. The computer program 1320a and / or computer program product 1310a may thus provide means for performing any steps of the network node 200 as herein disclosed. On this computer readable means 1330, a computer program 1320b can be stored, which computer program 1320b can cause the processing circuitry 310 and thereto operatively coupled entities and devices, such as the communications interface 320 and the storage medium 330, to execute methods according to embodiments described herein. The computer program 1320b and / or computer program product 1310b may thus provide means for performing any steps of the repeater node 300 as herein disclosed.

[0122] In the example of Fig. 13, the computer program product 1310a, 1310b is illustrated as an optical disc, such as a CD (compact disc) or a DVD (digital versatile disc) or a Blu-Ray disc. The computer program product 1310a, 1310b could also be embodied as a memory, such as a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM), or an electrically erasable programmable read-only memory (EEPROM) and more particularly as a non-volatile storage medium of a device in an external memory such as a USB (Universal Serial Bus) memory or a Flash memory, such as a compact Flash memory. Thus, while the computer program 1320a, 1320b is here schematically shown as a track on the depicted optical disk, the computer program 1320a, 1320b can be stored in any way which is suitable for the computer program product 1310a, 131 Ob.

[0123] The inventive concept has mainly been described above with reference to a few embodiments.

[0124] However, as is readily appreciated by a person skilled in the art, other embodiments than the ones disclosed above are equally possible within the scope of the inventive concept, as defined by the appended patent claims.

Claims

CLAIMS1 . A method for repeater-assisted localization of UEs (110a: 110d), wherein the method is performed by a network node (200), and wherein the method comprises: performing (S104) an iterative localization procedure, wherein each iteration of the localization procedure comprises: transmitting (S104-2) a triggering signal to the UEs (110a: 110d) and a current set of repeater configurations to at least one repeater node (300) to be used for the repeater-assisted localization of the UEs (110a:110d); receiving (S104-4) a current set of localization signals from at least some of the UEs (110a: 110d) directly and / or via reflection at the at least one repeater node (300), based on the current set of repeater configurations for the iteration; performing (S104-6) a localization of said at least some of the UEs (110a:110d) based on the current set of localization signals; and selecting (S104-8) an updated set of repeater configurations to be used in a next iteration, wherein the updated set of repeater configurations is selected based on the localization of said at least some of the UEs (110a: 110d) as performed based on the current set of localization signals and on the current set of repeater configurations.

2. The method according to claim 1, wherein the method further comprises: receiving (S102) a capability report about the at least one repeater node (300) pertaining to a capability of the at least one repeater node (300) to participate in the repeater-assisted localization of the UEs (110a: 110d), and wherein the set of repeater configurations is selected in accordance with the capability report.

3. The method according to claim 1 , wherein performing the localization of said at least some of the UEs (110a: 110d) comprises estimating a respective location and / or trajectory for each of said at least some of the UEs (110a: 110d).

4. The method according to claim 1 , wherein the localization of said at least some of the UEs (110a: 110d) for the current iteration is a refined localization of said at least some of the UEs(110a: 110d) for a previous iteration.

5. The method according to claim 1, wherein a first iteration is performed for localizing a first group of the UEs (110a: 110d), wherein a second iteration, subsequent to the first iteration, is performed for localizing a second group of the UEs (110a: 110d), and wherein the second group of UEs (110a: 110d) is an extension of the first group of UEs (110a: 110d).

6. The method according to claim 1 , wherein the set of repeater configurations indicates beam configurations to be used by the at least one repeater node (300), and wherein the beam configurations for a second iteration comprises narrower beam widths than the beam configurations for a first iteration.

7. The method according to claim 1, wherein the triggering signal for a first iteration indicates a set of time resources in which the UEs (110a: 110d) are to transmit a first set of localization signals.

8. The method according to claim 1 , wherein the set of repeater configurations for a first iteration indicates time resources and beam configurations and / or polarizations to be used by each at least one repeater node (300) in the time resources.

9. The method according to claim 8, wherein the set of repeater configurations for the first iteration indicates a beam sweep to be made by the at least one repeater node (300) in the time resources.

10. The method according to claim 1, wherein the triggering signal for a second iteration indicates a set of time resources in which the UEs (110a:110d) are to transmit a second set of localization signals, wherein the time resources are indicated per UE for the UEs (110a:110d) localized in a first iteration.11 . The method according to claim 10, wherein the time resources are not indicated per UE for UEs (110a: 110d) not localized in the first iteration.

12. The method according to claim 1 , wherein the set of repeater configurations for a second iteration indicates time resources and beam configurations to be used in the time resources, wherein the beam configurations specify which beam to be used by each at least one repeater node (300) in each of the time resources.

13. The method according to claim 1 , wherein the set of repeater configurations for a second iteration indicates time resources and which polarization to be used by each at least one repeater node (300) in which of the time resources.

14. The method according to claim 1, wherein the localization signals are composed of pilot signals, and wherein each pilot signal comprises an indicator identifying the UE having transmitted the pilot signal.

15. The method according to claim 14, wherein the triggering signal indicates how many pilot signals to be transmitted by each of the UEs (110a: 110d).

16. The method according to claim 15, wherein there are as many repeater configurations as there are pilot signals.

17. A method for repeater-assisted localization of UEs (110a: 110d), wherein the method is performed by a repeater node (300), and wherein the method comprises: performing (S204) an iterative repeater-assisted localization procedure, wherein each iteration of the repeater-assisted localization procedure comprises: receiving (S204-4) a current set of repeater configurations from the network node (200) to be used for reflecting a current set of localization signals; and reflecting (S204-6) the current set of localization signals as received from at least some of the UEs (110a: 110d) towards the network node (200) based on the current set of repeater configurations.

18. The method according to claim 17, wherein the method further comprises: transmitting (S202) a capability report to the network node (200) pertaining to a capability of the repeater node (300) to participate in the repeater-assisted localization of the UEs (110a:110d).

19. The method according to claim 18, wherein the capability of the repeater node (300) relates to at least one of:- beamforming capabilities of the repeater node (300),- switching delay between different beams at the repeater node (300),- switching delay between uplink and downlink at the repeater node (300),- polarization properties of the repeater node (300), and- support of single- or dual-directional localization.

20. The method according to claim 17, wherein each iteration of the repeater-assisted localization procedure further comprises:reflecting (S204-2) a triggering signal as received from the network node (200) towards the UEs (110a:110d).21 . The method according to claim 17, wherein the set of repeater configurations for a first iteration indicates time resources and beam configurations and / or polarizations to be used by the repeater node (300) in the time resources.

22. The method according to claim 21 , wherein the set of repeater configurations for the first iteration indicates a beam sweep to be made by the repeater node (300) in the time resources.

23. The method according to claim 17, wherein the set of repeater configurations for a second iteration indicates time resources and beam configurations to be used in the time resources, wherein the beam configurations specify which beam to be used by the repeater node (300) in each of the time resources.

24. The method according to claim 17, wherein the set of repeater configurations for a second iteration indicates time resources and which polarization to be used by the repeater node (300) in each of the time resources.

25. The method according to claim 17, wherein the repeater node (300) is either a network-controlled repeater node (300) or a reconfigurable intelligent surface node.

26. A network node (200) for repeater-assisted localization of UEs (110a: 110d), the network node (200) comprising processing circuitry (210), the processing circuitry being configured to cause the network node (200) to: perform an iterative localization procedure, the processing circuitry (210) further being configured to cause the network node (200) to in each iteration of the localization procedure: transmit a triggering signal to the UEs (110a: 110d) and a current set of repeater configurations to at least one repeater node (300) to be used for the repeater-assisted localization of the UEs (110a:110d); receive a current set of localization signals from at least some of the UEs (110a: 110d) directly and / or via reflection at the at least one repeater node (300), based on the current set of repeater configurations for the iteration;perform a localization of said at least some of the UEs (110a: 110d) based on the current set of localization signals; and select an updated set of repeater configurations to be used in a next iteration, wherein the updated set of repeater configurations is selected based on the localization of said at least some of the UEs (110a:110d) as performed based on the current set of localization signals and on the current set of repeater configurations.

27. The network node (200) according to claim 26, further being configured to perform the method according to any of claims 2 to 16.

28. A repeater node (300) for repeater-assisted localization of UEs (110a: 110d), the repeater node (300) comprising processing circuitry (310), the processing circuitry being configured to cause the repeater node (300) to: perform an iterative repeater-assisted localization procedure, the processing circuitry (310) further being configured to cause the repeater node (300) to in each iteration of the repeater-assisted localization procedure: receive a current set of repeater configurations from the network node (200) to be used for reflecting a current set of localization signals; and reflect the current set of localization signals as received from at least some of the UEs (110a: 110d) towards the network node (200) based on the current set of repeater configurations.

29. The repeater node (300) according to claim 28, further being configured to perform the method according to any of claims 18 to 25.

30. A computer program (1320a) for repeater-assisted localization of UEs (110a: 110d), the computer program comprising computer code which, when run on processing circuitry (210) of a network node (200), causes the network node (200) to: perform (S104) an iterative localization procedure, the computer program further comprising computer code which, when run on the processing circuitry (210) of the network node (200), causes the network node (200) to in each iteration of the localization procedure:transmit (S104-2) a triggering signal to the UEs (110a: 110d) and a current set of repeater configurations to at least one repeater node (300) to be used for the repeater-assisted localization of the UEs (110a:110d); receive (S104-4) a current set of localization signals from at least some of the UEs (110a: 110d) directly and / or via reflection at the at least one repeater node (300), based on the current set of repeater configurations for the iteration; perform (S104-6) a localization of said at least some of the UEs (110a:110d) based on the current set of localization signals; and select (S104-8) an updated set of repeater configurations to be used in a next iteration, wherein the updated set of repeater configurations is selected based on the localization of said at least some of the UEs (110a:110d) as performed based on the current set of localization signals and on the current set of repeater configurations.31 . A computer program (1320b) for repeater-assisted localization of UEs (110a: 110d), the computer program comprising computer code which, when run on processing circuitry (310) of a repeater node (300), causes the repeater node (300) to: perform (S204) an iterative repeater-assisted localization procedure, the computer program further comprising computer code which, when run on the processing circuitry (310) of the repeater node (300), causes the repeater node (300) to in each iteration of the repeater-assisted localization procedure: receive (S204-4) a current set of repeater configurations from the network node (200) to be used for reflecting a current set of localization signals; and reflect (S204-6) the current set of localization signals as received from at least some of the UEs (110a: 110d) towards the network node (200) based on the current set of repeater configurations.

32. A computer program product (1310a, 1310b) comprising a computer program (1320a, 1320b) according to at least one of claims 30 and 31 , and a computer readable storage medium (1330) on which the computer program is stored.

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