Handling of malfunction in a repeater node

Abstract

There is provided techniques for handling malfunction in a repeater node. A method is performed by a network node. The method comprises detecting malfunction of the repeater node with respect to an expected functionality of the repeater node. The expected functionality is based on a given configuration of the repeater node. That the repeater node is malfunctioning is detected by an observed functionality of the repeater node deviating from the expected functionality for the given configuration. The method comprises selecting a reconfiguration for the repeater node based on the detected malfunction. The method comprises sending information to the repeater node pertaining to the selected reconfiguration.

Description

[0001] HANDLING OF MALFUNCTION IN A REPEATER NODE

[0002] TECHNICAL FIELD

[0003] Embodiments presented herein relate to a method, a network node, a computer program, and a computer program product for handling malfunction in a repeater node.

[0004] BACKGROUND

[0005] In general terms, different technologies have been considered and proposed to increase the data rate and support the increasing number of user equipment (UE) in wireless communication system. Som examples are network densification and millimeter wave (mmW) communications. Network densification generally refers to the deployment of multiple access points of different types in, e.g., metropolitan areas. Particularly, (small) radio nodes, such as relays, integrated access and backhaul nodes, repeaters, etc., might be deployed to support existing macro base stations serving the UEs.

[0006] One issue with network densification is that the increased number of access points potentially also increases the number of hardware and / or software failures in the network, thus resulting in a degraded communication performance. One cause for such degraded communication performance could be due to malfunctioning repeaters. In case a malfunctioning repeater is not handled correctly, the result might be a degradation of the received power at the intended receivers.

[0007] One way to handle malfunctioning repeaters, or other types of access points, is to perform a manual inspection of the repeater, or to perform an inspections based on images of the repeater as captured by unmanned aerial vehicles, or the like. However, such inspections may not be possible or economically viable in all scenarios, as the repeater might be deployed in rural areas, suburban areas, on top of a building, or even in the sky, where physical access to the repeater is limited.

[0008] Hence, there is still a need for improved repeater malfunction detection and compensation procedures.

[0009] SUMMARY

[0010] An object of embodiments herein is to enable detection of, and compensation for, malfunctioning repeaters.

[0011] A particular object is to enable such detection and compensation without the use of manual inspection or unmanned aerial vehicles, or the like.

[0012] According to a first aspect there is presented a method for handling malfunction in a repeater node. The method is performed by a network node. The method comprises detecting malfunction of the repeater node with respect to an expected functionality of the repeater node. The expected functionality is based on a given configuration of the repeater node. That the repeater node is malfunctioning is detected by an observed functionality of the repeater node deviating from the expected functionality for the given configuration. The method comprises selecting a reconfiguration for the repeater node based on the detected malfunction. The method comprises sending information to the repeater node pertaining to the selected reconfiguration.

[0013] According to a second aspect there is presented a network node for handling malfunction in a repeater node. The network node comprises processing circuitry. The processing circuitry is configured to cause the network node to detect malfunction of the repeater node with respect to an expected functionality of the repeater node. The expected functionality is based on a given configuration of the repeater node. That the repeater node is malfunctioning is detected by an observed functionality of the repeater node deviating from the expected functionality for the given configuration. The processing circuitry is configured to cause the network node to select a reconfiguration for the repeater node based on the detected malfunction. The processing circuitry is configured to cause the network node to send information to the repeater node pertaining to the selected reconfiguration.

[0014] According to a third aspect there is presented a network node for handling malfunction in a repeater node. The network node comprises a detect module configured to detect malfunction of the repeater node with respect to an expected functionality of the repeater node. The expected functionality is based on a given configuration of the repeater node. That the repeater node is malfunctioning is detected by an observed functionality of the repeater node deviating from the expected functionality for the given configuration. The network node comprises a select module configured to select a reconfiguration for the repeater node based on the detected malfunction. The network node comprises a send module configured to send information to the repeater node pertaining to the selected reconfiguration.

[0015] According to a fourth aspect there is presented a computer program for handling malfunction in a repeater node. 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 detect malfunction of the repeater node with respect to an expected functionality of the repeater node. The expected functionality is based on a given configuration of the repeater node. That the repeater node is malfunctioning is detected by an observed functionality of the repeater node deviating from the expected functionality for the given configuration. One action comprises the network node to select a reconfiguration for the repeater node based on the detected malfunction. One action comprises the network node to send information to the repeater node pertaining to the selected reconfiguration.

[0016] According to a fifth aspect there is presented a computer program product comprising a computer program according to the fourth 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.

[0017] Advantageously, by (dynamically) reconfiguring the repeater node, these aspects make it possible to use repeater nodes in a robust way in the presence of short- or long-term impairments. Advantageously, these aspects enable detection of, and compensation for, malfunctioning repeaters without the use of manual inspection or unmanned aerial vehicles, or the like.

[0018] Advantageously, these aspects therefore enable zero-touch maintenance in the repeater node-assisted network via signaling, thus avoiding the use of manual inspection as well as the deployment of unmanned aerial vehicles for performing the inspection.

[0019] 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.

[0020] 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.

[0021] BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The inventive concept is now described, by way of example, with reference to the accompanying drawings, in which:

[0023] Fig. 1 is a schematic diagram illustrating a communication network according to embodiments;

[0024] Fig. 2 is a schematic illustration of a repeater node implemented as a network-controlled repeater according to an embodiment;

[0025] Fig. 3 is a schematic illustration of a repeater node implemented as a RIS node according to an embodiment;

[0026] Figs. 4 and 5 are flowcharts of methods according to embodiments;

[0027] Fig. 6 is a schematic diagram showing structural units of a network node according to an embodiment;

[0028] Fig. 7 is a schematic diagram showing functional modules of a network node according to an embodiment; and

[0029] Fig. 8 shows one example of a computer program product comprising computer readable storage medium according to an embodiment.

[0030] DETAILED DESCRIPTION

[0031] 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.

[0032] 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 110. 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 communicate with one or more UEs 120 by means of assistance from the repeater node 110. The repeater node 110 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 110 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. As illustrated by wireless links 130, 140, the network node 200 communicates with the UE 120 via the repeater node 110. For this purpose the repeater node 110 comprises an element array comprising individual elements, such as antenna elements or atoms, for facilitating reflection, or forwarding, or signals, between the network node 200 and the UE 120. The type of element array and elements will depend on the type of repeater node 110. One reason for the network node 200 to communicate with the UE 120 via the repeater node 110 might be that the line-of-sight path between some of the UEs served by the network node and the network node is blocked by some physical object 150. As schematically illustrated at reference numeral 160 there is a risk that the repeater node 110 is malfunctioning. Such malfunctioning could impact the repeater node's ability to reflect, or forward, signals sent over the wireless links 130, 140. How to combat such malfunctioning will be disclosed in further detail below.

[0033] 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.

[0034] There could be different types of repeater nodes 110. In some non-limiting examples, and as will be disclosed next, the repeater node 110 can be either a network-controlled repeater node, an RIS node (in its active or passive format), or even a non-terrestrial network (NTN) node.

[0035] An example where the repeater node 110 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 110 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 110, 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, an uplink signal as transmitted by the UE 120 can be received over an access link 140 and forwarded to the network node 200 over a backhaul link 130. For this purpose, the repeater node 110 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 130 and the access link 140. 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. An NTN node can be regarded as a network-controlled repeater being deployed in e.g., a satellite system and provided with further functionality than a traditional network-controlled repeater.

[0036] An example where the repeater node 110 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 114 of reflecting elements 118, 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 130, 140) 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 112 that is configured to change the settings of the elements 118 to thereby change how an impinging electro-magnetic wave is reflected (in terms of direction, beamforming, etc.). In some examples, the elements 118 are grouped into sub-arrays 116a, 116b. The controller 112 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 small (such as in the order of 2-3 dB), 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 118 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. As noted above there is a risk that the repeater node 110 is malfunctioning. Such malfunctioning could impact the repeater node's ability to reflect, or forward, signals sent over the wireless links 130, 140. In further detail, consider a repeater-assisted system in which one or more UEs communicate with a network node with the aid of one or more repeater nodes, e.g., network-controlled repeater devices, RIS devices, or NTN nodes.

[0037] The functioning of the repeater node components can be subject to adverse situations, for instance, a total failure in one of more of the components, a partial, or intermittent, failure due to the presence of environmental impairments, such as water precipitations, snowflakes, and freezing rain, to name just a few. Understanding such malfunctions based on manual inspection, or even inspections based on images of the repeater nodes as captured by unmanned aerial vehicles, may not be possible or economically viable, as the repeater nodes might be deployed in rural areas, suburban areas, on top of buildings, or even in the sky.

[0038] For this reason, it is beneficial to develop zero-touch malfunction detection and compensation procedures that are based on signaling. According to at least some of the herein disclosed embodiments, techniques are disclosed to identify possible malfunctioning of repeater nodes as caused by any of the above described adverse situations, and then to mitigate any identified issue provoked by this malfunctioning via proper reconfigurations of the repeater nodes. This results in a robust operation, enabling the repeater nodes to assist the wireless communication even under adverse scenarios.

[0039] The embodiments disclosed herein in particular relate to techniques for handling malfunction in a repeater node. 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 a network node, causes the network node to perform the method.

[0040] Fig. 4 is a flowchart illustrating embodiments of methods for handling malfunction in a repeater node 110. The methods are performed by the network node 200. The methods are advantageously provided as computer programs 820.

[0041] At least some of the herein disclosed embodiments are based on determining and compensating for the malfunctioning of a repeater node with zero-touch. This can in some embodiments be achieved by monitoring different sub-arrays of the repeater node to detect the malfunction, or more generally to detected that an observed functionality of the repeater node deviates from the expected functionality of the repeater node for a given configuration. In particular, the network node 200 is configured to perform step S106.

[0042] S106: The network node 200 detects malfunction of the repeater node 110 with respect to an expected functionality of the repeater node 110. The expected functionality is based on a given configuration of the repeater node 110. That the repeater node 110 is malfunctioning is detected by an observed functionality of the repeater node 110 deviating from the expected functionality for the given configuration. The configurations may be for the downlink operation of the repeater node and / or the uplink operation of the repeater node. Based on the determined malfunction, proper reconfiguration can be determined. In particular, the network node 200 is configured to perform step S108.

[0043] S108: The network node 200 selects a reconfiguration for the repeater node 110 based on the detected malfunction.

[0044] The reconfiguration can then be sent to the repeater node 110 for the repeater node 110 to be reconfigured. That is, the network node 200 is configured to perform step S110.

[0045] S110: The network node 200 sends information to the repeater node 110 pertaining to the selected reconfiguration.

[0046] In this way, the method makes it possible to determine and compensate for the repeater node's malfunctions via signaling.

[0047] Embodiments relating to further details of handling malfunction in a repeater node 110 as performed by the network node 200 will now be disclosed with continued reference to Fig. 4.

[0048] In general terms, that the repeater node 110 is malfunctioning implies that communication of signals is malfunctioning in the repeater node 110. That is, that the repeater node 110 is malfunctioning implies that the repeater node's capability to transmit, receive, or reflect, signals to / from / between other communication devices is degraded, impaired, or negatively affected. As disclosed above, the repeater node 110 uses at least one element array comprising individual elements for communicating the signals with at least one communication device. Hence, that the repeater node 110 is malfunctioning implies that at least part of the at least one element array, such as one or more of the elements, is malfunctioning. This in turn implies that either one or more individual elements is malfunctioning, or that one or more subarrays 116a, 116b is malfunctioning. Further, depending on the type of repeater node 110, the malfunctioning might relate to the capability of the repeater node 110 to transmit signals to other communication devices (where the malfunctioning is in a transmitter part of the repeater node 110), the capability of the repeater node 110 to receive signals from other communication devices (where the malfunctioning is in a receiver part of the repeater node 110), and / or the capability of the repeater node 110 to reflect signals between two communication device. Further, the expected functionality of the repeater node 110 generally is to forward signals between communication devices (such as between the network node 200 and one or more UEs 120 served by the network node 200). That the observed functionality of the repeater node 110 is deviating from the expected functionality for the given configuration might therefore be indicated by the forwarding of signals between these communication devices via the repeater node 110 is unsuccessful, or at least that the performance (in terms or received power, received quality, bit rate, etc.) of the communication between these communication devices via the repeater node 110 is poorer than expected for the given configuration of the repeater node 110. In turn, this might indicate that the repeater node 110 is malfunctioning. Here, and as will be disclosed in more detail below, the different configurations of the repeater node 110 generally relate to different settings of the at least one element array (or subarrays thereof) of the repeater node 110. Hence, by testing different subarrays of the repeater node 110 with different configurations, it can be determined which subarray of the repeater node 110 that is malfunctioning.

[0049] In general terms, the expected functionality of the repeater node is dependent on the capabilities of the repeater node. In some aspects, the network node therefore receives a capability report about the repeater node. That is, in some embodiments, the network node 200 is configured to perform (optional) step S102:

[0050] S102: The network node 200 receives a capability report about the repeater node 110.

[0051] In general terms, the capability report pertains to the repeater node's capability to function as a repeater. In some non-limiting examples, the capability report specifies at least any, or any combination of: the beamforming capability of the repeater node 110, the number and / or types of beams the repeater node 110 is capable of generating, an on / off capability for different sub-arrays 116a, 116b of an element array 114 in the repeater node 110, the number of antenna elements per element array 114, antenna constellations of the antenna elements, malfunctioning detection capabilities in the repeater node 110. In yet further non-limiting examples, the capability report additionally or alternatively specifies at least any, or any combination of: the repeater-Fwd reliance on repeater-MT, latency requirements for the repeater node 110 to apply dynamic configurations, switching delay, power allocation capabilities per sub-array 116a, 116b, full duplex operation capabilities.

[0052] The capability report might be received either from the repeater node itself, from an Operations, Administration and Maintenance (0AM) node, from another network node, etc. Further, the capability report might be received using different types of signaling, such as through radio resource control (RRC) signaling, a medium access control (MAC) control element (CE), through uplink control information (UCI), etc.

[0053] In some aspects, the network node understands the need for detecting the malfunctioning. This understanding is based on a trigger. Obtaining such a trigger is thus an action that might precede the actual detection in step S106. Hence, in some embodiments, the network node 200 is configured to perform (optional) step S104:

[0054] S104: The network node 200 obtains a trigger to detect the malfunction of the repeater node 110.

[0055] In some aspects, the trigger is obtained by means of a performance report from at least one UE 120 served by the network node 200 via the repeater node 110. In other aspects, the trigger is generated by the network node 200 itself, for example based on measurements made on signals received from the at least one UE 120 via the repeater node 110. The performance report indicates at least a temporary performance drop or performance deviation of the at least one UE 120.

[0056] The performance drop might be a drop in received power, or a reception of negative acknowledgements (NACKs) in one or more consecutive slots. The performance deviation might be a drop in expected signal quality with respect to some guaranteed bitrate, or similar. In further examples, the performance report includes information from the repeater node itself, wherein the information indicates that the repeater node might be malfunctioning.

[0057] In some examples, the temporary performance drop or performance deviation lasts longer than a predefined threshold. In some examples, the network node 200 needs to obtain such performance reports from more than one UE for the network node to be triggered to detect the malfunction of the repeater node 110. This can be used to rule out that it instead is one particular UE 120 that is malfunctioning or being blocked by some physical object being placed between the UE 120 and the repeater node 110.

[0058] As disclosed above, the network node in step S106 detects that the repeater node 110 is malfunctioning. There might be different ways for the network node to determine that the observed functionality of the repeater node 110 is deviating from the expected functionality for a given configuration, as specified in step S106. Further aspects relating thereto will be disclosed next.

[0059] In some aspects, detecting the malfunction in the repeater node is based on direction indication from the repeater node. In particular, in some embodiments, the expected functionality of the repeater node 110 corresponds to an expected direction from which signals are expected to be received by the network node 200 from the repeater node 110, and the observed functionality of the repeater node 110 corresponds to an observed direction from which signals are received by the network node 200 from the repeater node 110. For example, depending on the hardware capabilities, the repeater node may be equipped with a built-in functionality for malfunction detection. Then, the repeater node can run the detection functionality, and report to the network node correspondingly via its control channel. The repeater node could have some standardized test procedure, or protocol, that it runs regularly, or it may be instructed by the network node (via the control channel) where, for instance, the network node triggers and configures the repeater node to run its internal malfunction detection process. The result from the test is then communicated to the network node. This standardized test procedure may involve network nodes and UEs in a controlled fashion, but (if possible) the repeater node could perform it by itself internally. This is at the cost of implementational and computational complexity at the repeater node.

[0060] In another aspect, the network node detects the malfunction by sending reference signals and receiving feedback from either the repeater node or its served UEs. Different ways for the network node to detect the malfunction by means of reference signals will be disclosed next.

[0061] In some aspects, detecting the malfunction in the repeater node is based on network node configurating different configurations for different sub-arrays 116a, 116b of the repeater node. In particular, in some embodiments, detecting the malfunction of the repeater node 110 comprises the network node 200 configuring the repeater node 110 with a set of configurations. Each configuration corresponds to a respective expected functionality. Each configuration is to be applied for a respective sub-array 116a, 116b of an element array 114 in the repeater node 110. The network node 200 can then monitor a relative performance of the repeater node 110 for each of the configurations in order to determine whether or not an observed functionality of the repeater node 110 deviates from the expected functionality for each given configuration and thereby detect the malfunction of the repeater node 110. Further, in case the performance is (almost) the same for different sub-arrays , the network node can conclude that the performance drop is due to, e.g., blockage, shadowing, etc. and not that the repeater node is malfunctioning.

[0062] In some aspects, detecting the malfunction in the repeater node is based on network node configurating different ON / OFF configurations for different sub-arrays of the repeater node. The ON / OFF configurations might be explicit or implicit. Here, an implicit indication can be based on the lack of beam, or reflection, configuration for a subarray or based on indicating a specific NULL beam, or reflection, configuration. The sub-arrays may be overlapping or non-overlapping. For example, in some embodiments, the configurations correspond to the repeater node 110 selectively switching on and off the respective sub-arrays 116a, 116b of the element array 114, and the repeater node 110 applying a beamforming configuration to the respective sub-arrays 116a, 116b being switched on. The network node 200 can then monitor a relative performance of the repeater node 110 for each of the beamforming configurations in order to determine whether or not an observed functionality of the repeater node 110 deviates from the expected functionality for each given beamforming configuration and thereby detect the malfunction of the repeater node 110.

[0063] Hence, the repeater node's elements might be divided into different sub-arrays and the network node might monitor the performance of the repeater node separately for each of these sub-arrays. In this way, since the subarrays can more or less be regarded as co-located and thus experience the same channel quality, if one of the sub-arrays is malfunctioning, this sub-array will have considerably different performance (e.g., of received power, phase, etc.) compared to other sub-arrays. That is, in some embodiments, that the repeater node 110 is malfunctioning is detected by the performance indication for one or more of the sub-arrays 116a, 116b being more than a threshold worse than the performance indication for one or more other of the sub-arrays 116a, 116b.

[0064] In some aspects, dividing the repeater node into sub-arrays is based on the repeater node capabilities for beamforming, ON / OFF capabilities of the elements (i.e., the antennas in an NCR or NTN node or the reflecting elements in the IRS). That is, in some embodiments, the sub-arrays 116a, 116b are defined based on the beamforming capability of different elements in the element array 114, the on / off capability of the different elements in the element array 114, the number antenna constellations of the elements, and / or the number of subarray constellations.

[0065] In some non-limiting examples, the beamforming configuration pertains to any, or any combination of: reflection angle or direction, forwarding beam direction, time instants and / or periodicity during which the repeater node 110 is to apply the beamforming configuration for each sub-array 116a, 116b. In some non-limiting examples, the beamforming configuration further pertains to the beam width (such as wide beams, semi-wide beams or narrow beams) that is to be used by the repeater node. In general terms, the malfunctioning of the repeater node can then be detected by means of performance indications for each of the configurations. In some examples, the performance indication for both downlink operation and uplink operation pertains to the measurements of one or more of channel gain, reference signal received power (RSRP), signal to interference plus noise ratio (SI NR), signal to noise ratio (SNR), reference signal received quality (RSRQ), received phase information.

[0066] For downlink operation, the network node transmits at least one reference signal according to the determined configuration for the ON sub-array(s), to be forwarded by the ON sub-array(s). After transmitting the at least one reference signal, the network node then receives an indication from the device, or devices, such as one or more UEs, intended to receive the reference signal. That is, in some embodiments, detecting the malfunction of the repeater node 110 comprises the network node 200, upon having configured the repeater node 110 with the set of configurations, (1) transmitting a reference signal towards the repeater node 110 for reflection towards UE 120 served by the network node 200 whilst the repeater node 110 applies the configurations, and (2) receiving a respective performance indication of each of the configurations from the served UE 120. Here, the at least one reference signal might be a synchronization signal block (SSB) signal or a channel state information reference signal (CSI-RS).

[0067] For uplink operation, the at least one reference signal might be transmitted either by the network node itself and then reflected back to the network node via the repeater node, or transmitted by a UE 120 served by the network node 200 and then reflected towards the network node via the repeater node.

[0068] That is, in some embodiments, the malfunction of the repeater node 110 comprises the network node 200, upon having configured the repeater node 110 with the set of configurations, (1) transmitting reference signal towards the repeater node 110 for reflection back towards the network node 200 whilst the repeater node 110 applies the configurations, and (2) observing a respective performance indication of each of the configurations by measuring on the reference signal for each of the configurations. This embodiment will below be referred to as embodiment 1.

[0069] In some embodiments, detecting the malfunction of the repeater node 110 comprises the network node 200, upon having configured the repeater node 110 with the set of configurations, configuring (1) UE 120 served by the network node 200 to transmit reference signal towards the repeater node 110 for reflection towards the network node 200 whilst the repeater node 110 applies the configurations, and (2) observing a respective performance indication of each of the configurations by measuring on the reference signal for each of the configurations. This embodiment will below be referred to as embodiment 2.

[0070] Further, by one or the combination of embodiment 1 and embodiment 2, the network node may detect whether the malfunction is at the network node-side and / or the UE-side of the repeater node. For embodiment 1 the network node can determine whether there is a malfunction in the network node-side of the repeater node or not. Further, if embodiment 1 does not indicate any malfunction of the repeater node, but embodiment 2 shows malfunction of the repeater node, then it can be determined that the malfunction is at the UE-side of the repeater node.

[0071] In some aspects, the malfunction can be detected using the digital twin concept, where a digital twin of the network node can be updated in (almost) real-time based on reports from sensors, UEs, network nodes, repeaters, etc. Hence in some embodiments, the network node 200 has access to a digital twin of the repeater node 110, and the expected functionality of the repeater node 110 is provided by the digital twin. Here, any abnormal changes in the digital twin would indicate that something is malfunctioning in the repeater node. Additionally, the digital twin can be trained with different malfunctions for the digital twin to recognize, or classify, when certain malfunctions have occurred.

[0072] As disclosed above, in step S108 the network node 200 selects a reconfiguration for the repeater node 110 based on the detected malfunction. In this respect, there could be different types of reconfigurations that are selected based on the malfunction detected in step S106. In some non-limiting examples, the reconfiguration for the repeater node 110 pertains to any, or any combination of: the operation mode for the different sub-arrays 116a, 116b of the element array 114 in the repeater node 110, power control for the different sub-arrays 116a, 116b, on / off configuration for the different sub-arrays 116a, 116b, beamforming and / or reflection configuration for the different sub-arrays 116a, 116b, codebook utilization for the different sub-arrays 116a, 116b. Here, the reconfiguration may be periodic, semi-persistent or dynamic.

[0073] As disclosed above, in step S110 the network node 200 sends information to the repeater node 110 pertaining to the selected reconfiguration.

[0074] In some aspects, the network node 200 sends explicit reconfiguration to the repeater node. Thus, in some embodiments, the information sent to the repeater node 110 is the selected reconfiguration itself. In other aspects, the network node 200 informs the repeater node 110 about the determined malfunction. That is, in some embodiments, the information sent to the repeater node 110 indicates that the repeater node 110 is malfunctioning. In this way, the network node 200 might inform the repeater node 110 so that repeater node 110 can perform self-healing or otherwise by itself determine how to handle the malfunction. In some aspects, signaling the repeater node about the determined reconfiguration may be based on, e.g., RRC signaling, a MAC- CE, or downlink control information (DCI). Sending information to the repeater node about the determined reconfiguration may be performed jointly or separately for different sub-arrays.

[0075] In this way, the network node can determine the malfunctions in the repeater node with zero-touch and reconfigure the repeater node accordingly. Particularly, the repeater reconfiguration can be selected coherently to achieve the best performance given its instantaneous operating conditions and identified malfunctioning components. This results in robust performance in the repeater-assisted networks. Reference is next made to the flowchart of Fig. 5 for triggering detection of malfunction in a repeater node.

[0076] S201 : The network node monitors the functioning of the repeater node.

[0077] S202: The network node checks whether the repeater node functions as expected or not. If yes, step S201 is entered again, possibly after some time delay. If no, step S203 is entered.

[0078] S203: The network node triggers detection of malfunction of the repeater node.

[0079] Fig. 6 schematically illustrates, in terms of a number of structural 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 810 (as in Fig. 8), 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).

[0080] 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.

[0081] Thus the processing circuitry 210 is thereby arranged to execute methods as herein disclosed. 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. The network node 200 may further comprise a communications (comm.) interface 220 at least configured for communications with other entities, functions, nodes, and devices, such as in Fig. 1 and Fig. 2. As such the communications interface 220 may comprise one or more transmitters and receivers, comprising analogue and digital components. 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.

[0082] Fig. 7 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. 7 comprises a number of functional modules; a detect module 210 configured to perform step S106, a select module 210 configured to perform step S108, and a send module 210 configured to perform step S110. The network node 200 of Fig. 7 may further comprise a number of optional functional modules, such as any of a receive module 210 configured to perform step S102, and an obtain module 210 configured to perform step S104.

[0083] In general terms, each functional module 210a:21 Oe may in one embodiment be implemented only in hardware and in another embodiment with the help of software, i.e., the latter embodiment having computer program instructions stored on the storage medium 230 which when run on the processing circuitry makes the network node 200 perform the corresponding steps mentioned above in conjunction with Fig 7. It should also be mentioned that even though the modules correspond to parts of a computer program, they do not need to be separate modules therein, but the way in which they are implemented in software is dependent on the programming language used. Preferably, one or more or all functional modules 210a:21 Oe 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 configured to from the storage medium 230 fetch instructions as provided by a functional module 210a:210e and to execute these instructions, thereby performing any steps as disclosed herein.

[0084] 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, 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 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 is illustrated in Fig. 6 the processing circuitry 210 may be distributed among a plurality of devices, or nodes. The same applies to the functional modules 210a:21 Oe of Fig. 7 and the computer program 820 of Fig. 8.

[0085] 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).

[0086] Fig. 8 shows one example of a computer program product 810 comprising computer readable storage medium 830. On this computer readable storage medium 830, a computer program 820 can be stored, which computer program 820 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 820 and / or computer program product 810 may thus provide means for performing any steps as herein disclosed.

[0087] In the example of Fig. 8, the computer program product 810 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 810 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 820 is here schematically shown as a track on the depicted optical disk, the computer program 820 can be stored in any way which is suitable for the computer program product 810.

[0088] The inventive concept has mainly been described above with reference to a few embodiments. 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 handling malfunction in a repeater node (110), wherein the method is performed by a network node (200), and wherein the method comprises: detecting (S106) malfunction of the repeater node (110) with respect to an expected functionality of the repeater node (110), wherein the expected functionality is based on a given configuration of the repeater node (110), and wherein that the repeater node (110) is malfunctioning is detected by an observed functionality of the repeater node (110) deviating from the expected functionality for the given configuration; selecting (S108) a reconfiguration for the repeater node (110) based on the detected malfunction; and sending (S110) information to the repeater node (110) pertaining to the selected reconfiguration.

2. The method according to claim 1, wherein the method further comprises: receiving (S102) a capability report about the repeater node (110), wherein the capability report specifies at least any, or any combination of: a beamforming capability of the repeater node (110), number and / or types of beams the repeater node (110) is capable of generating, an on / off capability for different sub-arrays (116a, 116b) of an element array (114) in the repeater node (110), number of antenna elements per element array (114), antenna constellations of the antenna elements, malfunctioning detection capabilities in the repeater node (110).

3. The method according to claim 1 or 2, wherein the method further comprises: obtaining (S104) a trigger to detect the malfunction of the repeater node (110), wherein the trigger is obtained by means of a performance report from at least one user equipment (120) served by the network node (200) via the repeater node (110), wherein the performance report indicates at least a temporary performance drop or performance deviation of the at least one user equipment (120), wherein the temporary performance drop or performance deviation lasts longer than a predefined threshold.

4. The method according to any preceding claim, wherein the expected functionality of the repeater node (110) corresponds to an expected direction from which signals are expected to be received by the network node (200) from the repeater node (110), and wherein the observed functionality of the repeater node (110) corresponds to an observed direction from which signals are received by the network node (200) from the repeater node (110).

5. The method according to any preceding claim, wherein detecting the malfunction of the repeater node (110) comprises the network node (200) configuring the repeater node (110) with a set of configurations where each configuration corresponds to a respective expected functionality, where each configuration is to be appliedfor a respective sub-array (116a, 116b) of an element array (114) in the repeater node (110), and monitoring a relative performance of the repeater node (110) for each of the configurations.

6. The method according to claim 5, wherein the configurations correspond to the repeater node (110) selectively switching on and off the respective sub-arrays (116a, 116b) of the element array (114), and the repeater node (110) applying a beamforming configuration to the respective sub-arrays (116a, 116b) being switched on.

7. The method according to claims 2 and 6, wherein the sub-arrays (116a, 116b) are defined based on the beamforming capability of different elements in the element array (114), the on / off capability of the different elements in the element array (114), number antenna constellations of the elements, and / or number of sub-array constellations.

8. The method according to claim 6 or 7, wherein the beamforming configuration pertains to any, or any combination of: reflection angle or direction, forwarding beam direction, time instants and / or periodicity during which the repeater node (110) is to apply the beamforming configuration for each sub-array (116a, 116b).

9. The method according to claim 6, 7 or 8, wherein detecting the malfunction of the repeater node (110) comprises the network node (200), upon having configured the repeater node (110) with the set of configurations, transmitting a reference signal towards the repeater node (110) for reflection towards user equipment (120) served by the network node (200) whilst the repeater node (110) applies the configurations, and receiving a respective performance indication of each of the configurations from the served user equipment (120).

10. The method according to claim 6, 7 or 8, wherein detecting the malfunction of the repeater node (110) comprises the network node (200), upon having configured the repeater node (110) with the set of configurations, transmitting reference signal towards the repeater node (110) for reflection back towards the network node (200) whilst the repeater node (110) applies the configurations, and observing a respective performance indication of each of the configurations by measuring on the reference signal for each of the configurations.11 . The method according to claim 6, 7 or 8, wherein detecting the malfunction of the repeater node (110) comprises the network node (200), upon having configured the repeater node (110) with the set of configurations, configuring user equipment (120) served by the network node (200) to transmit reference signal towards the repeater node (110) for reflection towards the network node (200) whilst the repeater node (110) applies the configurations, and observing a respective performance indication of each of the configurations by measuring on the reference signal for each of the configurations.

12. The method according to claim 9, 10 or 11, wherein that the repeater node (110) is malfunctioning is detected by the performance indication for one or more of the sub-arrays (116a, 116b) being more than a threshold worse than the performance indication for one or more other of the sub-arrays (116a, 116b).

13. The method according to any preceding claim, wherein the network node (200) has access to a digital twin of the repeater node (110), and wherein the expected functionality of the repeater node (110) is provided by the digital twin.

14. The method according to any preceding claim, wherein the reconfiguration for the repeater node (110) pertains to any, or any combination of: operation mode for different sub-arrays (116a, 116b) of an element array (114) in the repeater node (110), power control for the different sub-arrays (116a, 116b), on / off configuration for the different sub-arrays (116a, 116b), beamforming and / or reflection configuration for the different sub-arrays (116a, 116b), codebook utilization for the different sub-arrays (116a, 116b).

15. The method according to any preceding claim, wherein the information sent to the repeater node (110) is the selected reconfiguration itself.

16. The method according to any preceding claim, wherein the information sent to the repeater node (110) indicates that the repeater node (110) is malfunctioning.

17. The method according to any preceding claim, wherein the repeater node (110) is a network-controlled repeater device, a reconfigurable intelligent surface device, or a non-terrestrial network, NTN, node.

18. A network node (200) for handling malfunction in a repeater node (110), the network node (200) comprising processing circuitry (210), the processing circuitry being configured to cause the network node (200) to: detect malfunction of the repeater node (110) with respect to an expected functionality of the repeater node (110), wherein the expected functionality is based on a given configuration of the repeater node (110), and wherein that the repeater node (110) is malfunctioning is detected by an observed functionality of the repeater node (110) deviating from the expected functionality for the given configuration; select a reconfiguration for the repeater node (110) based on the detected malfunction; and send information to the repeater node (110) pertaining to the selected reconfiguration.

19. A network node (200) for handling malfunction in a repeater node (110), the network node (200) comprising: a detect module (210c) configured to detect malfunction of the repeater node (110) with respect to an expected functionality of the repeater node (110), wherein the expected functionality is based on a given configuration of the repeater node (110), and wherein that the repeater node (110) is malfunctioning is detected by an observed functionality of the repeater node (110) deviating from the expected functionality for the given configuration;a select module (21 Od) configured to select a reconfiguration for the repeater node (110) based on the detected malfunction; and a send module (210e) configured to send information to the repeater node (110) pertaining to the selected reconfiguration.

20. The network node (200) according to claim 18 or 19, further being configured to perform the method according to any of claims 2 to 17.

21. A computer program (820) for handling malfunction in a repeater node (110), the computer program comprising computer code which, when run on processing circuitry (210) of a network node (200), causes the network node (200) to: detect (S106) malfunction of the repeater node (110) with respect to an expected functionality of the repeater node (110), wherein the expected functionality is based on a given configuration of the repeater node (110), and wherein that the repeater node (110) is malfunctioning is detected by an observed functionality of the repeater node (110) deviating from the expected functionality for the given configuration; select (S108) a reconfiguration for the repeater node (110) based on the detected malfunction; and send (S110) information to the repeater node (110) pertaining to the selected reconfiguration.

22. A computer program product (810) comprising a computer program (820) according to claim 21, and a computer readable storage medium (830) on which the computer program is stored.

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