Beam management for coverage enhancing devices

Abstract

A method of operating an access node of a communication network is provided. The method comprises obtaining, from a coverage enhancing device in coverage of the access node, a control message comprising information indicative of a presence of at least one receiving beam of the coverage enhancing device that fulfils at least one quality requirement. The access node may configure or control the coverage enhancing device based on the control message to facilitate beam management of the coverage enhancing device.

Description

[0001] D E S C R I P T I O N

[0002] BEAM MANAGEMENT FOR COVERAGE ENHANCING DEVICES

[0003] TECHNICAL FIELD

[0004] Various examples of the disclosure generally relate to coverage enhancing devices, such as network-controlled repeaters. Various examples specifically relate to beam management for coverage enhancing devices.

[0005] BACKGROUND

[0006] To improve a coverage area for wireless communication and support an increasing number of user equipment (UE), it is envisioned to use coverage enhancing devices (CEDs), such as Network Controlled Repeaters (NCRs) or re-configurable relaying devices (RRDs). RRDs are sometimes also referred to as reflective intelligent surfaces (RISs). CEDs can also be referred to as network enhancement devices since they generally enhance coverage, rank, and / or localizations. One example of RRDs is re- configurable reflective devices, sometimes also referred to as reflecting large intelligent surfaces (LISs).

[0007] An RRD / RIS can be implemented by an array of antennas that can reflect incident electromagnetic waves / signals. The array of antennas can be semi-passive. Semipassive can correspond to a scenario in which the antennas can impose a variable phase shift and typically provide no signal amplification.

[0008] NCRs can in some scenarios amplify a signal for each antenna element of a respective array; this is however optional. An NCR can implement one of reflection for coverage enhancement, amplify-forward for coverage enhancement, or decode-forward for coverage enhancement. Each antenna element may impose an antenna-element- specific amplitude gain and phase shift (i.e., provide signal amplification and variable phase shift). Oftentimes, operation of an NCR may be restricted to the analog domain, e.g., digital forward error correction may not be provided. An NCR may include multiple antenna arrays, e.g., one for receiving and one for transmitting. There may be signal processing in the baseband between receiving and transmitting.

[0009] In the Third Generation Partnership Project (3GPP) document TR 38.867 V1.0.0 (2022-09), the potentials and challenges of NCRs have been evaluated. The 3GPP discussions on NCR are currently continuing in a work-item and the regulatory phase will start. In simple words, NCR may be a normal repeater with beamforming capabilities and under the control of an access node (AN) of a network, e.g., a gNodeB (gNB) of the 5G-New Radio (5G-NR).

[0010] For a CED, an input spatial direction (or simply, input direction) from which incident signals on a radio link are accepted by a CED and an output spatial direction (or simply, output direction) into which the incident signals are redirected by the CED can be reconfigured by changing a phase relationship (and, where possible, amplitude relationship) between the antennas. This corresponds to configuring a spatial filter at the CED; or beamforming.

[0011] For example, an AN may transmit signals to a wireless communication device (e.g., UE, sometimes also referred to as a wireless terminal or a wireless transmit receive unit) via a CED, e.g., an NCR. The CED may accept or receive the incident signals from an input spatial direction and forward or transmit the incident signals in an output spatial direction to a wireless terminal.

[0012] In general, a CED, e.g., either an RRD / RIS or an NCR, may use antenna arrays with multiple antenna elements. As the number of antenna elements grows, the number of beams (either receiving beams and / or transmitting beams) grows in proportion to the number of antenna elements. Consequently, it may become more and more challenging to perform beam management for a CED.

[0013] SUMMARY

[0014] Therefore, a need exists for advanced techniques of facilitating beam management for a CED. This need is met by the features of the independent claims. The features of the dependent claims define examples.

[0015] A method of operating an access node of a communication network is provided. The method comprises obtaining, from a coverage enhancing device in coverage of the access node, a control message. The control message comprises information indicative of a presence of at least one receiving beam of the coverage enhancing device that fulfils at least one quality requirement.

[0016] A computer program or a computer-program product or a computer-readable storage medium includes program code to be executed by at least one processor. Executing the program code causes the at least one processor to perform a method of operating an access node of a communication network. The method comprises obtaining, from a coverage enhancing device in coverage of the access node, a control message. The control message comprises information indicative of a presence of at least one receiving beam of the coverage enhancing device that fulfils at least one quality requirement.

[0017] A node of a communication network is provided. The node includes control circuitry, the control circuitry being configured to obtain, from a coverage enhancing device in coverage of the access node, a control message. The control message comprises information indicative of a presence of at least one receiving beam of the coverage enhancing device that fulfils at least one quality requirement.

[0018] A method of operating a coverage enhancing device is provided. The coverage enhancing device is controlled by an access node of a communication network. The method comprises performing channel measurement on a plurality of receiving beams. The method also comprises determining at least one receiving beam from the plurality of receiving beams for which at least one quality requirement is fulfilled based on the channel measurements. The method further comprises providing, to the access node, a control message comprising information indicative of a presence of the at least one receiving beam. A computer program or a computer-program product or a computer-readable storage medium includes program code to be executed by at least one processor. Executing the program code causes the at least one processor to perform a method of operating a coverage enhancing device. The coverage enhancing device is controlled by an access node of a communication network. The method comprises performing channel measurement on a plurality of receiving beams. The method also comprises determining at least one receiving beam from the plurality of receiving beams for which at least one quality requirement is fulfilled based on the channel measurements. The method further comprises providing, to the access node, a control message comprising information indicative of a presence of the at least one receiving beam.

[0019] A coverage enhancing device is provided. The coverage enhancing device is controlled by an access node of a communication network. The coverage enhancing device includes control circuitry. The control circuitry is configured to perform channel measurement on a plurality of receiving beams. The control circuitry is also configured to determine at least one receiving beam from the plurality of receiving beams for which at least one quality requirement is fulfilled based on the channel measurements. The control circuitry is further configured to provide, to the access node, a control message comprising information indicative of a presence of the at least one receiving beam.

[0020] A communication system is provided. The system includes the node and the coverage enhancing device described above.

[0021] It is to be understood that the features mentioned above and those yet to be explained below may be used not only in the respective combinations indicated, but also in other combinations or in isolation without departing from the scope of the invention.

[0022] BRIEF DESCRIPTION OF THE DRAWINGS

[0023] FIG. 1 schematically illustrates a communication system according to various examples.

[0024] FIG. 2 schematically illustrates aspects in connection with an analog signal processing module of a CED according to various examples. FIG. 3 schematically illustrates an exemplary scenario for determining receiving beams fulfilling at least one quality requirement according to various examples.

[0025] FIG. 4 illustrates details with respect to a communication system according to various examples.

[0026] FIG. 5 is a flowchart of a method according to various examples.

[0027] FIG. 6 is a flowchart of a further method according to various examples.

[0028] FIG. 7 is an exemplary signaling diagram of communication between a BS, a CED, and a UE according to various examples.

[0029] DETAILED DESCRIPTION OF EMBODIMENTS

[0030] Some examples of the present disclosure generally provide for a plurality of circuits or other electrical devices. All references to the circuits and other electrical devices and the functionality provided by each are not intended to be limited to encompassing only what is illustrated and described herein. While particular labels may be assigned to the various circuits or other electrical devices disclosed, such labels are not intended to limit the scope of operation for the circuits and the other electrical devices. Such circuits and other electrical devices may be combined with each other and / or separated in any manner based on the particular type of electrical implementation that is desired. It is recognized that any circuit or other electrical device disclosed herein may include any number of microcontrollers, a graphics processor unit (GPU), integrated circuits, memory devices (e.g., FLASH, random access memory (RAM), read only memory (ROM), electrically programmable read only memory (EPROM), electrically erasable programmable read only memory (EEPROM), or other suitable variants thereof), and software which co-act with one another to perform operation(s) disclosed herein. In addition, any one or more of the electrical devices may be configured to execute a program code that is embodied in a non-transitory computer readable medium programmed to perform any number of the functions as disclosed. In the following, embodiments of the invention will be described in detail with reference to the accompanying drawings. It is to be understood that the following description of embodiments is not to be taken in a limiting sense. The scope of the invention is not intended to be limited by the embodiments described hereinafter or by the drawings, which are taken to be illustrative only.

[0031] The drawings are to be regarded as being schematic representations and elements illustrated in the drawings are not necessarily shown to scale. Rather, the various elements are represented such that their function and general purpose become apparent to a person skilled in the art. Any connection or coupling between functional blocks, devices, components, or other physical or functional units shown in the drawings or described herein may also be implemented by an indirect connection or coupling. A coupling between components may also be established over a wireless connection. Functional blocks may be implemented in hardware, firmware, software, or a combination thereof.

[0032] Techniques are described that facilitate wireless communication between communication devices, e.g., ANs and / or UEs. A wireless communication system includes one or more transmitter communication devices and one or more receiver communication devices. In some examples, the wireless communication system can be implemented by nodes of a wireless communication network, e.g., a radio-access network (RAN) of a 3GPP-specified cellular network. In such a case, a Transmitter (TX) communication device or a Receiver (RX) communication device can be implemented by a base station (BS) of the RAN. The BS implements an AN.

[0033] According to various examples, a BS provides downlink (DL) transmission to one or more UEs. In other examples, one or more UEs respectively provide uplink (UL) transmissions to a respective BS.

[0034] For the sake of simplicity, various examples will be primarily described in the context of a UL transmission from one or more UEs to a BS. However, such techniques are equally applicable to a DL transmission from a BS of a cellular network to one or more UEs. According to the disclosure, the wireless communication system includes a CED. The CED supports UL and / or DL transmission. The CED may also support sidelink communication. According to the disclosure, the CED can be implemented by an NCR. This means that signals received at multiple receiving antenna elements of a receiving antenna array are combined to form a single signal and then distribute the single signal to multiple transmitting antenna elements of a transmitting antenna array. However, other implementation scenarios of the CED are possible, e.g., an RRD.

[0035] The CED may include multiple front-facing antenna arrays (sometimes also referred to as panels). These multiple front-facing antenna arrays are used to transmit signals to UEs or receive signals from UEs (rather than communicate with a BS). Each of the multiple front-facing antenna arrays may form various receiving / transmitting beams toward different spatial directions.

[0036] The CED may provide CED-assisted information to an AN connectable to the CED. Such CED-assisted information may facilitate the UL and / or DL transmission. The CED-assisted information may be implemented or encoded as a control message, e.g., a UL control message.

[0037] According to this disclosure, a CED in coverage of an AN provides a control message to the AN and the AN obtains the control message. The control message facilitates subsequent controlling or configuration of the CED. The control message comprises information indicative of a presence of at least one receiving beam of the CED that fulfils at least one quality requirement.

[0038] The term “indicative of the presence” means broadly that the control message indicates whether there is at least one receiving beam that fulfils the at least one quality requirement. The control message may or may not include additional information.

[0039] To provide such control message and information on the at least one receiving beam, the CED can perform local measurements. The CED can detect signals or measure power. The CED can perform channel measurements. Such techniques are based on the finding that according to examples the CED has the freedom to perform such background measurements without coordination from a control node, e.g., during a time slot in which the CED does not forward signals between one or more UEs and an AN, l.e. , a coverage enhancing functionality of the CED is in an off state.

[0040] The control message is, in some examples, provided pro-actively by the CED. l.e., the control message is not requested by the AN or queried by the AN. The CED may proactively provide the control message responsive to one or more reporting criteria being met. The CED can locally determine whether the one or more reporting criteria are being met. These reporting criteria can be predetermined. For example, the CED may execute measurements to determine whether or not at least one receive beam exists that fulfills the at least one quality requirement. Responsive to at least one beam fulfilling the at least one quality requirement, the CED can provide the control message. If there is no receive beam that fulfills the at least one quality requirement, the CED may not report, i.e. , not provide the at least one control message. It would also be possible that the CED aggregates information, e.g., across time. For instance, the CED may provide the control message if the at least one receiving beam is present for an extended, predetermined duration. Summarizing, conditional proactive reporting is thus possible. The AN may not need to query the control message.

[0041] Similarly, as a general rule, it is possible that the CED performs the local measurement without being instructed to do so by the AN. The CED may proactively execute the local measurements, e.g., when not providing forwarding functionality between the AN and any terminals.

[0042] Alternatively or additionally, the background measurements can also be performed with coordination from a control node of the CED, e.g., an AN. In such a scenario, the AN may schedule dedicated time and / or frequency resources to the CED for performing the background measurements. For example, the time and / or frequency resources may be scheduled / selected in one or more time slots in which the coverage enhancing functionality of the CED is in an off state.

[0043] Alternatively or additionally, when the CED connects to the AN for the first time, the CED may be configured by the AN with a default setting in which the CED is configured to perform the background measurements as soon as the coverage enhancing functionality of the CED transitions into the off state, e.g., from an on state. In such a scenario, the background measurements may be controlled or scheduled by the AN in an implicit manner. I.e. , the AN can simply schedule or control the on-off state of the coverage enhancing functionality of the CED, and the CED can decide and perform the background measurements by default in the off state of the coverage enhancing functionality.

[0044] According to this disclosure, the on-off state of the coverage-enhancing functionality of the CED can be controlled / indicated / configured by the AN using an explicit indication with on or off state, e.g., via dynamic or semi-static signalling, or an on-off pattern such as periodic / semi-static on-off pattern. Alternatively, or additionally, implicit indication via signalling for other side-control information, e.g., beam, or DL / UL configuration may be utilized.

[0045] Details with respect to the background measurement will be described further below.

[0046] Such information conveyed by the control message may be referred to as assistance information for beam management. The BS can use such assistance information in the beam management. The assistance information can facilitate fast discovery of UEs in the neighbourhood of the BS.

[0047] According to various examples, each of the at least one receiving beam may include beams for receiving signals from one or more UE.

[0048] According to various examples, the control message may be carried by the Physical Uplink Control Channel (PUCCH). The PUCCH may be the same as that of legacy UE. For example, the PUCCH may be in a short format of one or two symbols and the control message may explicitly inform / tell the AN, by configuring the one or two symbols of the PUCCH to be “1” or “0”, that there is at least one receiving beam of the CED that fulfils the at least one quality requirement.

[0049] Additionally or alternatively, the control message may implicitly inform / tell the AN that there is at least one receiving beam of the CED that fulfils the at least one quality requirement by configuring the control message to comprise at least one of a beam index of the at least one receiving beam, a respective pair of azimuth and elevation angles of spatial directions of the at least one receiving beam, or a count of the at least one receiving beam. I.e. , the control message may comprise information indicative of at least one of a beam index of the at least one receiving beam, a respective pair of azimuth and elevation angles of spatial directions of the at least one receiving beam, or a count of the at least one receiving beam.

[0050] According to various examples, all the receiving beams of an individual antenna array of the CED may be predefined / preconfigured with different beam indices based on a direction of each receiving beam, i.e., in a static manner. For example, the receiving beams may be predefined in a way like Synchronization Signal Block (SSB) beams. Thus, each of the receiving beams can be differentiated using a respective beam index, e.g., a digit. This can be referred to as a beam codebook.

[0051] For example, the at least one receiving beam may comprise three different receiving beams and the three receiving beams respectively have beam indices 2, 5, and 6. Thus, the CED may provide, to the AN, the control message comprising the three beam indices 2, 5, and 6. Such a control message, i.e., the three beam indices, implicitly indicate that there are three receiving beams of the CED that fulfils the at least one quality requirement.

[0052] According to various examples, all the receiving beams of an individual antenna array of the CED may be predefined / preconfigured with different azimuth and elevation angle pairs based on a direction of each receiving beam. For example, the CED may provide, to the AN, the control message comprising three pairs of azimuth and elevation angles of three different receiving beams. The three pairs of azimuth and elevation angles implicitly indicate that there are three receiving beams of the CED that fulfils the at least one quality requirement.

[0053] According to various examples, a count of the at least one receiving beam of the CED that fulfils the at least one quality requirement may be determined based on either beam indices or azimuth and elevation angle pairs as explained above. Such a count, e.g., 3, of the at least one receiving beam may be determined by the CED and then provided to the AN. Upon receiving the control message comprising the count of the at least one receiving beam, the AN is informed that there are three receiving beams of the CED that fulfils the at least one quality requirement.

[0054] Alternatively, or additionally, the control message may comprise information indicative of an originator of signals received on the at least one receiving beam. For example, such an originator may be a UE and the information indicative of the UE may be an identifier associated with the UE, e.g., a subscriber identifier or a UE identifier. For example, the subscriber identifier may comprise a Subscription Permanent Identifier (SUPI) and the UE identifier may comprise a Permanent Equipment Identifier (PEI). Such scenarios are helpful to discover UEs, e.g., in a cell edge scenario. For instance, a UE may be connected to another access node and may repetitively transmit or broadcast messages that include the identifier of the UE identity. This can then be reported by the CED and the access node may take appropriate actions, e.g., informed the serving further access nodes that the UE is in coverage so that a handover may be planned. In a further scenario, UEs that are newly connecting to the communications network can be discovered. For instance, UEs that execute a randomaccess procedure and signal the random-access preamble - as a further example of an identifier indicative of the originator - can be detected. UEs can be previously operating in a disconnected or idle mode, e.g., after being switched off or being in a power saving mode.

[0055] According to various examples, the control message may alternatively or additionally comprise information indicative of at least one of a channel measurement report of a channel measurement performed on the at least one receiving beam by the coverage enhancing device, a power spectral density, or a received signal strength of signals on the at least one receiving beam.

[0056] For example, the CED may perform channel measurement on a plurality of its beams and obtain a channel measurement report comprising channel state information (CSI) of each of the plurality of beams. Then, the CED may determ ine / select, based on the at least one quality requirement, corresponding channel state information of each of the at least one receiving beam and provide, to the AN, a channel measurement report comprising the corresponding channel state information of each of the at least one receiving beam. Alternatively, the CED may first determine, based on the at least one quality requirement, the at least one receiving beam and perform channel measurement merely for each of the at least one receiving beam.

[0057] The power spectral density and the received signal strength may be both obtained based on the signals received on respective receiving beams of the CED. For example, the CED may respectively receive signals on a plurality of its beams and determine a respective power spectral density and / or a respective received signal strength of the signals received on each of the respective receiving beams of the CED. Then, the power spectral density and / or the received signal strength of signals on the at least one receiving beam can be determined / selected based on the respective power spectral density and / or the respective received signal strength of the signals received on each of the plurality of beams of the CED.

[0058] According to various examples, the control message may comprise information indicative of the at least one quality requirement. The CED is able to select between different quality requirements in some examples. For instance, the CED can be able to select between received signal strength and power spectral density. The CED may make such selection depending on which quality metric is more appropriate depending on the reception circumstances. In such a scenario, the CED can inform the access node of the particular quality requirement (enhance the underlying metric) used by the CED.

[0059] For example, the at least one quality requirement may comprise a power spectral density measured on the at least one receiving beam being above a predetermined threshold. Accordingly, the control message may comprise the predetermined threshold associated with the power spectral density.

[0060] Additionally, or alternatively, the at least one quality requirement may comprise a received signal strength of signals measured on the at least one receiving beam being above a predetermined threshold. Accordingly, the control message may comprise the predetermined threshold associated with the received signal strength.

[0061] According to various examples, upon obtaining the control message, the AN may determine signalling for controlling / configuring the CED based on the control message. For example, the AN may control / configure one or more behaviours of the CED in a beam management protocol based on the CED-assisted information. In another example, the AN may ignore the CED-assisted information based on, e.g., a predefined criterion.

[0062] For example, before the AN configures a beam sweep at the CED, the CED may first indicate / provide to the AN the at least one receiving beam of the CED that fulfils the at least one quality requirement. The at least one receiving beam may correspond to the most likely directions to find one or more UE. Then, the at least one receiving beams and / or corresponding transmitting beams may be scanned first. If UEs are found during the scanning, the beam sweep process can be terminated or avoided.

[0063] FIG. 1 schematically illustrates a communication system 100 according to various examples. The communication system 100 includes a BS 101 implementing an access node, a CED 109 and two UEs 102 and 105. Here, the CED 109 communicates on a back-haul link with a BS 101. Also, front-facing links towards one or more UEs 102, 105 are established. Further, an auxiliary data link 199 between the BS 101 and the CED 109 is established.

[0064] According to various examples, the auxiliary data link 199 may implement a Control link (C-link) to enable control information, e.g., UL and / or DL control information, exchanges between the CED 109 and the BS 101. The auxiliary data link may be based on a Uu interface. The behaviours of the CED 109 may be controlled / configured according to control information received by the CED 109 from the BS 101. In addition, the CED 109 may provide CED-assisted information to the BS 101 via the auxiliary data link 199. Beam management assistance information can be provided. For example, the control message described herein may be provided by the CED 109 to the BS 101 via the auxiliary data link 199.

[0065] As shown in FIG. 1 , a beam 679 is used by the CED 109 to communicate with the BS 101 via the back-haul link, and two beams 671 , 672 are respectively used by the CED 109 to communicate with the UEs 102 and 105 via the front-facing links. For example, the beam 679 and the beam 671 may be used to forward signals between the BS 101 and the UE 102, and the beam 679 and the beam 672 may be used to forward signals between the BS 101 and the UE 105.

[0066] For DL communication, the beam 679 is a receiving beam, and the beams 671 , 672 are transmitting beams; for UL communication, the beam 679 is a transmitting beam, and the beams 671 , 672 are receiving beams.

[0067] As a general rule, the CED 109 may comprise either a single front-facing antenna array or multiple front-facing antenna arrays (not shown in FIG. 1 ). For a CED 109 comprising multiple front-facing antenna arrays, the beams 671 , 672 may be implemented by the same front-facing antenna array or different front-facing antenna arrays. This depends on how far the two UEs 102, 105 are spaced apart.

[0068] FIG. 2 schematically illustrates aspects in connection with an analog signal processing module 500 of a CED, e.g., the CED 109 of FIG. 1 , according to various examples. FIG. 2 schematically illustrates the connection between the backhaul antenna array 520 and the front-facing antenna array 510 of the CED 109. Each antenna element of the front-facing antenna array 510 (here exemplarily acting as an input (or receiving) antenna array, for UL communication) is associated with a corresponding phase shifter for configuring a spatial direction of a receiving beam, e.g., the beam 671 of FIG. 1 , for receiving signals from a UE, e.g., the UE 102 of FIG. 1. The signals received from the UE 102 are then added / combined to a single signal at a summation element 885. It is optional to use the amplifier, e.g., a variable gain amplifier. The combined single signal is then distributed by a splitting element 886 to multiple phase shifters of the backhaul antenna array 520 to be forwarded to the BS 101 of FIG. 1 . The multiple phase shifters of the backhaul antenna array 520 may be configured to form the beam 679 of FIG. 1 .

[0069] According to various examples, the CED 109 may be equipped with a measurement module for performing measurements on a plurality of receiving beams, e.g., all or a part of the receiving beams of the CED 109. At least one quality of the signals received on each of the plurality of receiving beams is determined. The at least one quality may comprise a power spectral density, a power, and / or a signal strength. Different hardware implementations of such measurement module are conceivable. For instance, the measurement module can include receiver circuitry. The measurement module can perform time-integrated measurements of power, to measure a power spectral density.

[0070] According to this disclosure, the at least one receiving beam may comprise a wide receiving beam and / or a narrow receiving beam.

[0071] FIG. 3 schematically illustrates an exemplary scenario for determining receiving beams fulfilling at least one quality requirement according to various examples. FIG. 3 illustrates an exemplary scenario in which the CED 109 monitors signals respectively received from different receiving beams to determine at least one receiving beam that fulfils at least one quality requirement.

[0072] According to various examples, the CED 109 may have measured signals in the background, i.e., without having been explicitly configured by the BS 101 , and have detected received energy in beams not currently configured by the BS 101 . Based on the received energy in the beams, the CED 109 may have reached the conclusion that there are L settings of the spatial filters of the front-facing antenna array 510, i.e., beams, by which the CED 109 has received high power. These signals may be towards UEs, e.g., the UE 102 and / or 105, that try to connect to the system 100, or towards UEs at the cell edge that may be better served by the BS 101 associated with the CED 109. However, it could also be that said L directions point to the BS 101 itself. But this can be avoided since the CED is able to be aware of the Time Division Duplex (TDD) pattern and can therefore scan for power only in the UL.

[0073] In the scenario of FIG. 3, the CED 109 may toggle through different spatial filters associated with wide receiving beams 521 , 522, and 523, to configure phases of the phase shifters of the front-facing antenna array 510 of the CED 109. Accordingly, three signals are respectively received on the wide receiving beams 521 , 522, and 523. The three signals may be received during three different time periods and the different time periods may be continuous. By measuring the at least one quality, e.g., a signal strength, of each of the three signals, the strongest signal is determined to have been received on the wide receiving beam 522. Accordingly, a control message comprising information indicative of a presence of at least one receiving beam of the CED 109 that fulfils at least one quality requirement, i.e., the wide receiving beam 522, is provided to the BS 101 via the auxiliary data link 199. Accordingly, the BS 101 can control the CED to directly activate the wide receiving beam 522 to forward signals between the BS 101 and the UE 102 without a beam sweep, and thereby the BS 101 may not need to devote time and / or frequency resources for performing the beam sweep. Therefore, it is possible to significantly reduce the overhead of network resources.

[0074] As shown in FIG. 3, the direction of the wide receiving beam 522 may not perfectly align with the direct direction (i.e. , line-of-sight) between the CED 109 and the UE 102. As such, multiple narrow receiving beams 531 , 532, and 533 of the wide receiving beam 522 may be monitored. The multiple narrow receiving beams 531 , 532, and 533 may respectively cover a sub-area of the wide receiving beam 522. Three further signals are respectively received on the narrow receiving beams 531 , 532, and 533. The three signals may be received during three further different time periods and the further different time periods may be continuous. By measuring the at least one quality, e.g., a signal strength, of each of the three further signals, the strongest signal is determined to have been received on the narrow receiving beam 532. Accordingly, a control message comprising information indicative of a presence of at least one receiving beam of the CED 109 that fulfils at least one quality requirement, i.e., the narrow receiving beam 532, is provided to the BS 101 via the auxiliary data link 199.

[0075] As such, a two-stage determination of the presence of at least one receiving beam of the CED 109 that fulfils at least one quality requirement may be performed and thereby the BS 101 can directly activate the narrow receiving beam 532 to forward signals between the BS 101 and the UE 102 without a beam sweep. Compared with using the wide receiving beam 522, the using of the narrow receiving beam 532 for forwarding signals may further improve the quality of data communication between the BS 101 and the UE 102 and the energy efficiency of the CED 109.

[0076] This is only one example implementation of a background measurement process implemented at the CED to provide beam management assistance information to the BS 101. Other implementations are conceivable. According to various examples, the CED 109 may monitor signals respectively received from different receiving beams, e.g., the wide receiving beams 521 -523, or the narrow receiving beams 531-533 in an off state of a coverage enhancing functionality of the CED 109. In such an off state, the CED 109 is not able to forward signals between the BS 101 and other devices or UEs.

[0077] According to various examples, the different time periods during which signals are respectively received on the wide receiving beams 521 -523 and / or the narrow receiving beams 531-533 may be separated by one or more time periods during which the coverage enhancing functionality of the CED 109 is activated, i.e., in an on state.

[0078] The off state may be explicitly or implicitly configured by the BS 101 . For example, the BS 101 may provide scheduling information to the CED 109 to configure time durations during which the CED 109 is to operate in the on state. For instance, during the on state, the CED 109 can forward signals between another UE (not shown in FIG. 3) and the BS 101. Outside of these time durations, the CED 109 is in the off state.

[0079] The CED 109, according to examples, uses these idling times for background measurements to provide the assistance information. The CED 109 can scan various spatial directions and monitor spectral activity in these spatial directions and report thereon.

[0080] Alternatively, or additionally, the CED 109 may be equipped with a separate antenna that may have a spherical coverage corresponding to all or a part of the beam directions of the CED 109. The separate antenna may be used for determining receiving beams fulfilling at least one quality requirement.

[0081] According to various examples, the CED 109 may measure power of impinging signals broadcasted / transmitted by one or more UE. The CED 109 may perform measurements when the amplifier of FIG. 2 is shut / switched off.

[0082] FIG. 4 illustrates details with respect to a communication system 100 according to various examples. The system 100 comprises the BS 101 , the CED 109, and the UE 102 and 105. The UE 105 (not shown in FIG. 4) can be configured like the UE 102. The BS 101 includes a processor 1011 that can load program code from a memory 1015 and execute the program code. Executing the program code can cause the processor 1011 to perform techniques as described herein, e.g., obtaining CED- assisted information from the CED 109, configuring the CED 109; transmitting signals towards the CED 109, wherein the signals are for the UE 102 and / or the UE 105; receiving signals from the CED 109, wherein the signals originating from the UE 102 and / or the UE 105; using beamforming to direct signals towards the CED 109; etc.

[0083] The BS 101 further comprises a communication interface 1012 and an antenna array 1013 including multiple antenna elements. The communication between the BS 101 and the CED 109 is established via the antenna array 1013 and the communication interface 1012.

[0084] The UE 102 includes a processor 1021 and a memory 1025. The processor 1021 can load program code from the memory 1025 and execute the program code. Upon executing the program code, the processor can perform techniques as disclosed herein: e.g., receiving or transmitting signals via a wireless communication interface 1022 that accesses one or more antennas 1024; communicating messages with the BS 101 , e.g., measurement report messages indicative of a receive strength or receive angle or quality of reference signals, e.g., channel sounding signals or discovery signals; and etc.

[0085] According to various examples, the UE may be a legacy UE.

[0086] The CED 109 comprises the backhaul antenna array 520 and the front-facing antenna array 510. Either the backhaul antenna array 520 or the front-facing antenna array 510 comprises multiple antenna elements. The phase-relationship of the antenna elements can be re-configured by a processor 1091 to apply different spatial filters, i.e., apply different beams. For this, the processor 1091 can provide respective re-configuration commands via communication interfaces 1092 and 1095 to the backhaul antenna array 520 and the front-facing antenna array 510, respectively. The communication interfaces 1092, 1095 include respective antenna-specific phase shifters that can apply antenna-specific phase shifts for beamforming. The communication interfaces 1092, 1095 are coupled directly with each other.

[0087] Also illustrated in FIG. 4 is a memory 1093. The processor 1091 can load program code from the memory 1093 and execute the program code. Executing the program code causes the processor to perform techniques as described herein, e.g., providing CED-assisted information to the BS 101 ; obtaining configurations from the BS 101 via a respective communication interface 1092, e.g., an auxiliary data link 199; reconfiguring the antenna elements of the antenna arrays 510, 520, e.g., based on a configuration from the BS 101 ; activating / deactivating a coverage enhancing functionality of the CED 109; and etc.

[0088] FIG. 5 is a flowchart of a method 2000 according to various examples. The method 2000 of FIG. 5 is executed by an AN of a communication network, such as the BS 101 of the system 100. The method of FIG. 5 relates to operating the AN to facilitate beam management of a CED, e.g., the CED 109 of the system 100. Details of the method 2000 will be described below.

[0089] The method 2000 comprises, at block 2010, obtaining, from the CED in coverage of the AN, a control message comprising information indicative of a presence of at least one receiving beam of the CED that fulfils at least one quality requirement.

[0090] Details with respect to the control message, the at least one receiving beam (e.g., the wide receiving beam 522 and / or the narrow receiving beam 532 of FIG. 3), and the at least one quality requirement have been respectively described above.

[0091] Additionally, or optionally, the method 2000 may further comprise obtaining, from the CED, a capability message indicative of the CED being capable of determining the information indicative of the presence of the at least one receiving beam. For example, a respective capability message can be obtained, e.g., via the auxiliary link 199.

[0092] According to various examples, the capability message may be additionally or optionally indicative of the CED being capable of performing DL of the auxiliary link 199 and DL of the backhaul link in a Time-Division Multiplexing (TDM) way, and / or performing UL of the auxiliary link 199 and UL of the backhaul link in a TDM way.

[0093] Additionally, or optionally, the method 2000 may further comprise configuring the CED to perform channel measurements in an off state of a coverage enhancing functionality of the CED, the information indicative of the presence of the at least one receiving beam being based on the channel measurements. For example, the channel measurements may be performed using techniques as disclosed in connection with FIG. 3.

[0094] According to various examples, the coverage enhancing functionality of the CED may usually be in the off state. This may apply regardless of a further state associated with a further functionality of the CED for exchanging control information via the auxiliary link 199. The further state may comprise states the same as that of legacy UE Radio Resource Control (RRC) states, which may comprise RRC connected, RRC idle, and RRC inactive.

[0095] According to various examples, said configuring of the CED to perform the channel measurements may be based on the capability message. For example, the BS 101 may not configure the CED 109 to perform the channel measurements if the CED 109 is not able to determine the information indicative of the presence of the at least one receiving beam.

[0096] Additionally, or optionally, the method 2000 may further comprise, prior to obtaining the control message, configuring the CED to serve a terminal, e.g., the UE 105 of FIG. 1 (rather than the UE 102) using a front-facing beam, e.g., the beam 521 or 531 of FIG. 3, of the CED 109. The at least one receiving beam, e.g., either the beam 522 or 532 of FIG. 3, differs from the front-facing beam. For example, the UE 105 and 102 may be respectively served by the beams 521 and 532 in a TDM way.

[0097] Additionally, or optionally, the method 2000 may further comprise configuring, based on the control message, the CED to activate an on state of a coverage enhancing functionality of the CED. For example, activating the beam 522 or 532 of FIG. 3 may need to first activate the on state of the coverage enhancing functionality of the CED 109, and then configure the spatial filter of the front-facing antenna array 510 to form the beam 522 or 532.

[0098] Additionally, or optionally, the method 2000 may further comprise configuring the CED to activate one or more receiving beams, and the one or more receiving beams are selected from the at least one receiving beam. For example, referring to FIG. 3, the CED 109 may determine that the at least one receiving beam comprise the three beams 531 -533, and the BS 101 may select the beam 532 by comparing the at least one quality, e.g., a signal strength, associated with the signals respectively received on the three beams 531 -533.

[0099] Additionally, or optionally, the method 2000 may further comprise monitoring for one or more broadcasted signals when the CED activates the one or more receiving beams. For example, the one or more broadcasted signals may be broadcasted by one or more UEs, e.g., the UE 102 and / or 105, and forwarded by the CED 109 to the BS 101.

[0100] According to this disclosure, the method 2000 may be for use in a beam management protocol for configuring beams at the CED. For instance, in such beam management protocol, the BS 101 can probe a plurality of candidate beams by configuring a respective beam sweep at the CED 109. Amongst the plurality of candidate beams, the BS 101 can configure a prioritization based on the control message. For instance, the at least one receiving beam of the coverage enhancing device that fulfills the at least one quality requirement may be probed earlier and / or more often than other candidate beams of the plurality of candidate beams. Alternatively or additionally, narrower beams can be probed in a spatial region associated with the at least one receiving beam of the coverage enhancing device that fulfills the at least one quality requirement (if compared to regions in which the CED did not report the at least one quality requirement to be fulfilled). Such techniques can help to reduce a latency required for discovering UEs in a surrounding of the CED and / or for detecting the appropriate beam to serve a UE. Furthermore, control signaling overhead associated with the beam management protocol can be reduced, e.g., because a beam sweep can be aborted once the UE has been detected early on during the beam sweep due to the prioritization. The method 2000 disclosed herein may facilitate beam management of a CED. By obtaining a control message comprising information indicative of a presence of at least one receiving beam of the CED that fulfils at least one quality requirement, an AN may configure / control the CED to perform the beam management in an efficient manner. For example, the at least one receiving beam may be used to establish a priority list for a later or subsequent beam sweep. The later or subsequent beam sweep could therefore be initiated in the directions associated with the at least one receiving beam. When the at least one receiving beam comprise a single receiving beam, the AN can directly activate the single beam to forward signals between the AN and a UE without a beam sweep, and thereby the AN may not need to devote time and / or frequency resources for performing the beam sweep. Therefore, it is possible to significantly reduce the overhead of network resources.

[0101] FIG. 6 is a flow chart of a further method 3000 according to various examples. The method 3000 is executed by a CED of a communication network, such as the CED 109 of the system 100. The method 3000 relates to operating the CED to facilitate beam management of the CED. Details of the method 3000 will be described below.

[0102] At block 3010, performing channel measurement on a plurality of receiving beams.

[0103] For example, the channel measurements may be performed using techniques as disclosed in connection with FIG. 3.

[0104] At block 3020, determining at least one receiving beam from the plurality of receiving beams for which at least one quality requirement is fulfilled based on the channel measurements.

[0105] According to various examples, the channel measurement may be performed in an iterative manner until determining one receiving beam of the coverage enhancing device that fulfils at least one quality requirement.

[0106] At block 3030, providing, to the AN, a control message comprising information indicative of a presence of the at least one receiving beam. Details with respect to the control message, the at least one receiving beam (e.g., the wide receiving beam 522 and / or the narrow receiving beam 532 of FIG. 3), and the at least one quality requirement have been respectively described above.

[0107] According to various example, the method 3000 may further comprise being configured with one or more front-facing beams to serve one or more terminals and determining the plurality of receiving beams to differ from the one or more front-facing beams. For example, the CED 109 may be configured to serve the UE 105 of FIG. 1 (rather than the UE 102) using a front-facing beam, e.g., the beam 521 or 531 of FIG. 3, of the CED 109. The plurality of receiving beams may be determ ined / selected from other beams of the CED rather than the beam 521 or 531 , e.g., the beams 522, 523, 532, and 533. By determining the plurality of receiving beams to differ from the front-facing beams that currently serve other terminals, uncharted areas of the surrounding of the CED can be probed. New UEs can be detected. UEs can be detected that are currently not served via the CED.

[0108] Additionally, or optionally, the method 3000 may further comprise providing, to the AN, a capability message indicative of the coverage enhancing device being capable of determining the information indicative of the presence of the at least one receiving beam. For example, a respective capability message can be provided, e.g., via the auxiliary link 199.

[0109] Additionally, or optionally, the method 3000 may further comprise being configured to perform channel measurements in an off state of a coverage enhancing functionality of the coverage enhancing device and the information indicative of the presence of the at least one receiving beam may be determined based on the channel measurements. For example, the channel measurements may be performed using techniques as disclosed in connection with FIG. 3.

[0110] According to various examples, the coverage enhancing functionality of the CED may usually be in the off state. This may apply regardless of a further state associated with a further functionality of the CED for exchanging control information via the auxiliary link 199. The further state may comprise states the same as that of legacy UE Radio Resource Control (RRC) states, which may comprise RRC connected, RRC idle, and RRC inactive.

[0111] Additionally, or optionally, the method 3000 may further comprise being configured to activate an on state of a coverage enhancing functionality of the coverage enhancing device. For example, activating the beam 522 or 532 of FIG. 3 may need to first activate the on state of the coverage enhancing functionality of the CED 109, and then configure the spatial filter of the front-facing antenna array 510 to form the beam 522 or 532.

[0112] Additionally, or optionally, the method 3000 may further comprise being configured to activate one or more receiving beams, and the one or more receiving beams may be selected from the at least one receiving beam. For example, referring to FIG. 3, the CED 109 may determine that the at least one receiving beam comprise the three beams 531 -533, and the BS 101 may select the beam 532 by comparing the at least one quality, e.g., a signal strength, associated with the signals respectively received on the three beams 531 -533.

[0113] FIG. 7 is an exemplary signaling diagram of communication between a BS 101 , a CED 109, and a UE 102 to facilitate beam management of the CED 109.

[0114] The UE 102, at 6010, may broadcast or transmit signals 601 toward one or more frontfacing antenna array 510 of the CED 109. Such signals 601 may be associated with a random access procedure of the UE 102, or a data transmission procedure between the UE 102 and a further BS or a further CED. The CED 109, at 6020, may perform channel measurement 602 on a plurality of receiving beams. The plurality of receiving beams may be determ ined / selected from beams of a single front-facing antenna array 510 of the CED 109. The CED 109, at 6030, may determine at least one receiving beam 603 from the plurality of receiving beams for which at least one quality requirement is fulfilled based on the channel measurements 602. The CED 109, at 6040, may provide, to the BS 101 , a control message 604 comprising information indicative of a presence of the at least one receiving beam. The BS 101 , at 6050, may provide configuration information 605 to the CED 109 to configure / control the CED 109 to perform beam management. Said performing of beam management may comprise activating an on state of a coverage enhancing functionality of the coverage enhancing device, activating one or more receiving beams being selected from the at least one receiving beam, or performing a beam sweep in the directions associated with the at least one receiving beam.

[0115] Summarizing, various techniques disclosed herein may facilitate beam management of a CED. By using a control message comprising information indicative of a presence of at least one receiving beam of the CED that fulfils at least one quality requirement, an AN may configure / control the CED to perform the beam management in an efficient manner. The AN can use such assistance information as part of the beam management of the CED. For example, the at least one receiving beam may be used to establish a priority list for a later or subsequent beam sweep. The later or subsequent beam sweep could therefore be initiated in the directions associated with the at least one receiving beam. When the at least one receiving beam comprise a single receiving beam, the AN can directly activate the single beam to forward signals between the AN and a UE without a beam sweep, and thereby the AN may not need to devote time and / or frequency resources for performing the beam sweep. Therefore, it is possible to significantly reduce the overhead of network resources.

[0116] According to this disclosure, the following and other EXAMPLES have been described:

[0117] EXAMPLE 1 .A method of operating an access node of a communication network, the method comprising:

[0118] - obtaining, from a coverage enhancing device in coverage of the access node, a control message comprising information indicative of a presence of at least one receiving beam of the coverage enhancing device that fulfils at least one quality requirement.

[0119] EXAMPLE 2. The method of example 1 , wherein the control message comprises information indicative of at least one of a beam index of the at least one receiving beam, a respective pair of azimuth and elevation angles of spatial directions of the at least one receiving beam, or a count of the at least one receiving beam. EXAMPLE 3. The method of example 1 or 2, wherein the control message comprises information indicative of an originator of signals received on the at least one receiving beam; and / or wherein the control message comprises information indicative of the at least one quality requirement.

[0120] EXAMPLE 4. The method of any one of the preceding examples, wherein the control message comprises information indicative of at least one of a channel measurement report of a channel measurement performed on the at least one receiving beam by the coverage enhancing device, a power spectral density, or a received signal strength of signals on the at least one receiving beam.

[0121] EXAMPLE 5. The method of any one of the preceding examples, wherein the at least one quality requirement comprises a power spectral density measured on the at least one receiving beam being above a predetermined threshold; and / or wherein the at least one quality requirement comprises a received signal strength of signals measured on the at least one receiving beam being above a predetermined threshold.

[0122] EXAMPLE 6. The method of any one of the preceding examples, further comprising:

[0123] - obtaining, from the coverage enhancing device, a capability message indicative of the coverage enhancing device being capable of determining the information indicative of the presence of the at least one receiving beam.

[0124] EXAMPLE 7. The method of any one of the preceding examples, further comprising:

[0125] - configuring the coverage enhancing device to perform channel measurements in an off state of a coverage enhancing functionality of the coverage enhancing device, the information indicative of the presence of the at least one receiving beam being based on the channel measurements.

[0126] EXAMPLE 8. The method of any one of the preceding examples, further comprising: - configuring, based on the control message, the coverage enhancing device to activate an on state of a coverage enhancing functionality of the coverage enhancing device.

[0127] EXAMPLE 9. The method of any one of the preceding examples, further comprising:

[0128] - configuring the coverage enhancing device to activate one or more receiving beams, wherein the one or more receiving beams are selected from the at least one receiving beam.

[0129] EXAMPLE 10. A method of operating a coverage enhancing device controlled by an access node of a communication network, the method comprising:

[0130] - performing channel measurement on a plurality of receiving beams;

[0131] - determining at least one receiving beam from the plurality of receiving beams for which at least one quality requirement is fulfilled based on the channel measurements,

[0132] - providing, to the access node, a control message comprising information indicative of a presence of the at least one receiving beam.

[0133] Although the invention has been shown and described with respect to certain preferred examples, equivalents and modifications will occur to others skilled in the art upon the reading and understanding of the specification. The present invention includes all such equivalents and modifications and is limited only by the scope of the appended claims.

Claims

CLAIMS1 . A method of operating an access node of a communication network, the method comprising:- obtaining, from a coverage enhancing device in coverage of the access node, a control message comprising information indicative of a presence of at least one receiving beam of the coverage enhancing device that fulfils at least one quality requirement.

2. The method of claim 1 , wherein the control message comprises information indicative of at least one of a beam index of the at least one receiving beam, a respective pair of azimuth and elevation angles of spatial directions of the at least one receiving beam, or a count of the at least one receiving beam.

3. The method of claim 1 or 2, wherein the control message comprises information indicative of an originator of signals received on the at least one receiving beam.

4. The method of any one of the preceding claims, wherein the control message comprises information indicative of the at least one quality requirement.

5. The method of any one of the preceding claims, wherein the control message comprises information indicative of at least one of a channel measurement report of a channel measurement performed on the at least one receiving beam by the coverage enhancing device, a power spectral density, or a received signal strength of signals on the at least one receiving beam.

6. The method of any one of the preceding claims, wherein the at least one quality requirement comprises a power spectral density measured on the at least one receiving beam being above a predetermined threshold.

7. The method of any one of the preceding claims, wherein the at least one quality requirement comprises a received signal strength of signals measured on the at least one receiving beam being above a predetermined threshold.

8. The method of any one of the preceding claims, further comprising:- obtaining, from the coverage enhancing device, a capability message indicative of the coverage enhancing device being capable of determining the information indicative of the presence of the at least one receiving beam.

9. The method of any one of the preceding claims, further comprising:- configuring the coverage enhancing device to perform channel measurements in an off state of a coverage enhancing functionality of the coverage enhancing device, the information indicative of the presence of the at least one receiving beam being based on the channel measurements.

10. The method of claim 8 and claim 9, wherein said configuring of the coverage enhancing device to perform the channel measurements is based on the capability message.11 . The method of any one of the preceding claims, further comprising:- prior to obtaining the control message, configuring the coverage enhancing device to serve a terminal using a front-facing beam of the coverage enhancing device, wherein the at least one receiving beam differs from the front-facing beam.

12. The method of any one of the preceding claims, further comprising:- configuring, based on the control message, the coverage enhancing device to activate an on state of a coverage enhancing functionality of the coverage enhancing device.

13. The method of any one of the preceding claims, further comprising:- configuring the coverage enhancing device to activate one or more receiving beams, wherein the one or more receiving beams are selected from the at least one receiving beam.

14. The method of claim 13, further comprising:- monitoring for one or more broadcasted signals when the coverage enhancing device activates the one or more receiving beams.

15. The method of any one of the preceding claims, wherein the method is for use in a beam management protocol for configuring beams at the coverage enhancing device.

16. A method of operating a coverage enhancing device controlled by an access node of a communication network, the method comprising:- performing channel measurement on a plurality of receiving beams;- determining at least one receiving beam from the plurality of receiving beams for which at least one quality requirement is fulfilled based on the channel measurements,- providing, to the access node, a control message comprising information indicative of a presence of the at least one receiving beam.

17. The method of claim 16, further comprising:- being configured with one or more front-facing beams to serve one or more terminals, and- determining the plurality of receiving beams to differ from the one or more front-facing beams.

18. The method of claim 16 or 17, further comprising:- providing, to the access node, a capability message indicative of the coverage enhancing device being capable of determining the information indicative of the presence of the at least one receiving beam.

19. The method of any one of claims 16 to 18, further comprising:- being configured to perform channel measurements in an off state of a coverage enhancing functionality of the coverage enhancing device, the information indicative of the presence of the at least one receiving beam being determined based on the channel measurements.

20. The method of any one of claims 16 to 19, further comprising:- being configured to activate an on state of a coverage enhancing functionality of the coverage enhancing device.21 . The method of any one of claims 16 to 20, further comprising:- being configured to activate one or more receiving beams, wherein the one or more receiving beams are selected from the at least one receiving beam.

22. A network node of a communication network includes control circuitry, the control circuitry being configured to execute the method of any one of claims 1 to 15.

23. A coverage enhancing device includes control circuitry, the control circuitry being configured to execute the method of any one of claims 16 to 21 .

24. A communication system, the communication system comprising the network node of claim 22 and one or more coverage enhancing devices of claim 23.

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