Methods and apparatuses for controlling an antenna array

Abstract

Embodiments described herein relate to a methods and apparatuses for controlling an antenna array at a network node. A method performed by a controller node comprises controlling a first subset of antenna elements in the antenna array to provide a first beamforming pattern, wherein the first beamforming pattern is directed towards one or more first wireless devices in communication with the network node; and controlling a second subset of antenna elements in the antenna array to provide a second beamforming pattern, wherein the first beamforming pattern provides a first gain at a first angle associated with a first sidelobe of the first beamforming pattern, and the second beamforming pattern provides a second gain lower than the first gain at the first angle. The method further comprises responsive to a second power level detected on the second subset of antenna elements being less than a first power level detected on the first subset of antenna elements, controlling the first subset of antenna elements to provide a third beamforming pattern.

Description

[0001] METHODS AND APPARATUSES FOR CONTROLLING AN ANTENNA ARRAY

[0002] TECHNICAL FIELD

[0003] Embodiments described herein relate to a method and apparatus for controlling an antenna array. In particular, embodiments described herein provide methods for controlling the beamforming patterns provided by different subsets within an antenna array in order to mitigate interference that may be caused by a line-of-sight blocker.

[0004] BACKGROUND

[0005] The demand on the bitrate provided by a wireless communication system continues to increase. The fifth generation (5G) cellular system is being defined and developed. During this development the low frequency spectrum is being filled up and the higher frequency spectrum is being brought into use.

[0006] One technique to improve the 5G system performance is to use an advanced antenna system (AAS). A phased (or time delay) controlled array of antennas enables beamforming of the transmitted and received radio frequency (RF)-signals, which can be used to increase both capacity and coverage for a cellular system. Beamforming can be implemented in many ways, here the basic methods are briefly described.

[0007] Analog beamforming: The RF-signal or Local Oscillator (LO)-signal (used for up / down conversion of the wanted signal) is delayed / phase shifted (and / or the RF signal amplified) to create a beam. Several antenna feed points are connected to same Analog to Digital Convertor (ADC) or Digital to Analog Converter (DAC).

[0008] Digital beamforming - The wanted signal (example an Orthogonal Frequency Division Multiplexed (OFDM) modulated signal) is digitally delayed, phase shifted in time or frequency domain, and / or amplified to create a beam. Each antenna feed point is connected to a unique DAC or ADC.

[0009] Hybrid beamforming: A mix of Analog and Digital beamforming. In 5G cellular system a new frequency range is introduced, FR2 (24250 MHz - 52600 MHz). Due to these high frequencies, large antenna arrays (AAS) need to be built to ensure the Equivalent Isotropic Radiated Power (EIRP) and Equivalent Isotropic Sensitivity (EIS) performance to usable levels. The first-generation state of the art solution mmW base station (BS) has been based on analog beamforming to get a reasonable complexity, but as technology improves over time and the capacity need increases, the need for a hybrid beamforming solution increases too.

[0010] SUMMARY

[0011] The path loss in a communication link between a user equipment (UE) and base station (BS) will vary with, for example, the distance between the UE and the BS. This may not be a problem as the BS may be able to measure the power of the received signal and command the UE to lower or increase its transmitted power. This type of power control may be referred to an up-link power control loop.

[0012] However, the spectrum for specific band is normally divided into several sub-sections, that is owned by different operators. The power control loop will only control UEs that are connected to the operator specific BS. This could mean that a BS owned by “operator #1” is being blocked by a UE that is in communication with an “operator #2” BS. This problem is well known and is often referred to as the “near far problem”.

[0013] Figure 1 illustrates an example scenario in which the “near far problem” is occurring. In this example, a first operator, Operator #1 is serving its own UE, UE 101 at a cell border from a first base station 102 at the same time as the first base station 102 is being blocked by another UE, UE 103. The UE 103 is communicating at full power with a second base station 104 controlled by a second operator, operator #2. The incoming signal at the first base station 102 from UE 101 and UE 103 have different spatial angles.

[0014] In the example of Figure 1 it may be that the unwanted signal from UE 103 is at an angle where the first base station 102 is providing a sidelobe or grating lobe within a beamforming pattern, e.g. as illustrated by the example beamforming pattern 105.

[0015] The near-far problem may be especially problematic when the interfering UE (e.g. UE 103 in Figure 1) is close to the base station experiencing the interference. This is more likely when BS are placed at street level, which is a common 3GPP FR2 deployment. When wanted and unwanted signals arrive from different spatial directions (as would be the case in the example illustrated in Figure 1), the analog beamforming may be controlled to reduce the spatial spurious response in beam domain. A solution that works for 100% analog beamforming has been presented in WO2019 / 233612. As preferred architecture shift from 100% analog beam forming to hybrid beamforming there is a need to further enhance the algorithms defined in WO2019 / 233612, so that they take full benefit of the hybrid BF architecture.

[0016] According to some embodiments there is provided a method performed by a controller node for controlling an antenna array at a network node. The method comprises controlling a first subset of antenna elements in the antenna array to provide a first beamforming pattern, wherein the first beamforming pattern is directed towards one or more first wireless devices in communication with the network node and controlling a second subset of antenna elements in the antenna array to provide a second beamforming pattern, wherein the first beamforming pattern provides a first gain at a first angle associated with a first sidelobe of the first beamforming pattern, and the second beamforming pattern provides a second gain lower than the first gain at the first angle. The method further comprises responsive to a second power level detected on the second subset of antenna elements being less than a first power level detected on the first subset of antenna elements, controlling the first subset of antenna elements to provide a third beamforming pattern.

[0017] According to some embodiments there is provided a controller node for controlling an antenna array at a network node. The controller node comprises processing and a memory. The memory contains instructions executable by the processing circuitry whereby the controller node is operable to: control a first subset of antenna elements in the antenna array to provide a first beamforming pattern, wherein the first beamforming pattern is directed towards one or more first wireless devices in communication with the network node; control a second subset of antenna elements in the antenna array to provide a second beamforming pattern, wherein the first beamforming pattern provides a first gain at a first angle associated with a first sidelobe of the first beamforming pattern, and the second beamforming pattern provides a second gain lower than the first gain at the first angle; and responsive to a second power level detected on the second subset of antenna elements being less than a first power level detected on the first subset of antenna elements, control the first subset of antenna elements to provide a third beamforming pattern. According to some embodiments there is provided a computer program, comprising instructions which, when executed on at least one processor, cause the at least one processor to carry out the method as described above.

[0018] According to some embodiments there is provided a carrier containing the computer program as described above, wherein the carrier comprises one of an electronic signal, optical signal, radio signal or computer readable storage medium.

[0019] According to some embodiments there is provided a computer-readable medium comprising instructions that, when executed on at least one processor, cause the at least one processor to perform the method as described above.

[0020] According to some embodiments there is provided a computer program product comprising non transitory computer readable media having stored thereon a computer program as described above.

[0021] BRIEF DESCRIPTION OF THE DRAWINGS

[0022] For a better understanding of the embodiments of the present disclosure, and to show how it may be put into effect, reference will now be made, by way of example only, to the accompanying drawings, in which:

[0023] Figure 1 illustrates an example scenario in which the “near far problem” is occurring;

[0024] Figure 2 illustrates an antenna array 200 comprising a plurality of antenna elements;

[0025] Figure 3 illustrates a beamforming pattern produced from one of the subsets of antenna elements when bore sight steering is applied and a beamforming pattern produced from the one of the subsets of antenna elements 204 when 15 degrees beam steering is applied;

[0026] Figure 4 illustrates how amplitude tapering may be applied amongst the four RF lines within the subset of antenna elements 204, at a cost of very low loss in main lobe gain, to lower the gain within the sidelobes; Figure 5 illustrates a beamforming pattern 501 and a beamforming pattern 502;

[0027] Figure 6 illustrates a method for controlling an antenna array at a network node. The antenna array may comprise the antenna array 200 as illustrated in Figure 2;

[0028] Figure 7 illustrates an example antenna array comprising a plurality of antenna elements.

[0029] Figure 8 illustrates an example antenna array comprising a plurality of antenna elements;

[0030] Figures 9a and 9b illustrate example beamforming patterns;

[0031] Figure 10 illustrates an example implementation of the method of Figure 6;

[0032] Figure 11 illustrates an example method for monitoring the interference caused by a line- of-sight blocker;

[0033] Figure 12 illustrates a method for resetting the beamforming provided by an antenna array;

[0034] Figure 13 shows a controller node 1300 in accordance with some embodiments;

[0035] Figure 14 is a block diagram illustrating a controller node 1400 according to some embodiments.

[0036] DETAILED DESCRIPTION

[0037] Generally, all terms used herein are to be interpreted according to their ordinary meaning in the relevant technical field, unless a different meaning is clearly given and / or is implied from the context in which it is used. All references to a / an / the element, apparatus, component, means, step, etc. are to be interpreted openly as referring to at least one instance of the element, apparatus, component, means, step, etc., unless explicitly stated otherwise. The steps of any methods disclosed herein do not have to be performed in the exact order disclosed, unless a step is explicitly described as following or preceding another step and / or where it is implicit that a step must follow or precede another step. Any feature of any of the embodiments disclosed herein may be applied to any other embodiment, wherever appropriate. Likewise, any advantage of any of the embodiments may apply to any other embodiments, and vice versa. Other objectives, features and advantages of the enclosed embodiments will be apparent from the following description.

[0038] The following sets forth specific details, such as particular embodiments or examples for purposes of explanation and not limitation. It will be appreciated by one skilled in the art that other examples may be employed apart from these specific details. In some instances, detailed descriptions of well-known methods, nodes, interfaces, circuits, and devices are omitted so as not obscure the description with unnecessary detail. Those skilled in the art will appreciate that the functions described may be implemented in one or more nodes using hardware circuitry (e.g., analog and / or discrete logic gates interconnected to perform a specialized function, ASICs, PLAs, etc.) and / or using software programs and data in conjunction with one or more digital microprocessors or general purpose computers. Nodes that communicate using the air interface may have suitable radio communications circuitry. Moreover, where appropriate the technology can additionally be considered to be embodied entirely within any form of computer- readable memory, such as (ROM, EEPROM, Flash memory, a memory disc, RAM etc.) solid-state memory, magnetic disk, or optical disk containing an appropriate set of computer instructions that would cause a processor to carry out the techniques described herein.

[0039] Hardware implementation may include or encompass, without limitation, digital signal processor (DSP) hardware, a reduced instruction set processor, hardware (e.g., digital or analogue) circuitry including but not limited to application specific integrated circuit(s) (ASIC) and / or field programmable gate array(s) (FPGA(s)), and (where appropriate) state machines capable of performing such functions.

[0040] Certain aspects of the present disclosure and their embodiments may provide solutions to these or other challenges.

[0041] Particular embodiments are described more fully with reference to the accompanying drawings. Other embodiments, however, are contained within the scope of the subject matter disclosed herein. The disclosed subject matter should not be construed as limited to only the embodiments set forth herein; rather, these embodiments are provided by way of example to convey the scope of the subject matter to those skilled in the art. Embodiments described herein provide a method and apparatus, for example, for hybrid beamforming AAS radio, which enables fast detection of a direction of a line-of-sight blocker direction and allows for selection of a beamforming pattern that would provide spatial suppression in the direction of the line-of-sight blocker. It will be appreciated that when line-of-sight blockers are present the ADCs coupled to an antenna array may be experiencing issues with clipping. Therefore it may be desirable to reduce the gain in the direction of the line-of-sight blocker in order to reduce the amplitude being experienced by the ADCs.

[0042] Embodiments described herein enable for configuration of an analog beamformer in hybrid beamforming AAS, so that a sub-set of the antenna array have either different side lobe or grating lobe levels. The knowledge of the side or grating lobe gain levels may then be used to determine the angle of arrival of a line-of-sight blocker. Tapering may be used to subpress side lobes or beam steering may be used to shift grating lobes depending on angle of arrival of the signal from the line-of-sight blocker.

[0043] Embodiments described herein will be explained with reference to an example application of hybrid BF for mmW (e.g. as will be described with reference to Figure 2). It will however be appreciated that the embodiments described herein may be equally applied to using other frequency ranges and other partitioning between subarrays, or applied to analog beamforming and / or digital beamforming.

[0044] Figure 2 illustrates an antenna array 200 comprising a plurality of antenna elements. Each circle within the array represents an antenna element. The antenna array 200 is configured to provide an AAS performing hybrid BF for mmW.

[0045] Pairs of antenna elements are combined to static sub-arrays (e.g. 202). The RF signals obtained from four antenna ports coupled to four static sub-arrays are phase / time shifted and / or amplified in the analog domain in the RFIC that is placed behind the antenna elements and then combined / split in uplink (UL) / downlink (DL) in the analog domain. The particular four sub-arrays are, in this example, placed in a vertical orientation (e.g. as represented by 204) to provide a subset of antenna elements 204 which will generate sidelobes and potentially grating lobe(s) in the elevation direction. For UL the combined signal is then AD-converted so that it can be further processed in digital domain. In this example, full digital BF is used in azimuth domain. For illustration purposes an elevation element spacing of 0.63 lambda is assumed (lamda is the wavelength of carrier frequency), and it is assumed that analog beamforming is performed on the signals from the four antenna ports of the sub-arrays 202. A larger antenna distance than 0.5 lambda improves the performance of the antenna gain in a defined limited-service area (example + / - 15 degrees) due to a larger antenna area.

[0046] Since the subarrays in the example of Figure 2 are sized 2 x 1 , the effective sub-array phase center separation is 1 .26 lambda, which causes grating lobes to show up at even small elevation beam steering.

[0047] Figure 3 illustrates a beamforming pattern 301 produced from one of the subsets of antenna elements 204 when bore sight steering is applied and a beamforming pattern 302 produced from the one of the subsets of antenna elements 204 when 15 degrees beam steering is applied. It will be appreciated that the bore sight antenna gain has been normalised to 0. It will also be appreciated that mechanical tilt may be applied to the entire antenna area to change the actual direction of bore sight for the antenna array.

[0048] Herein, the term beamforming pattern is utilised to describe the pattern provided by a subset of antenna elements. It will be appreciated that the output of the entire array may effectively by combined to provide a composite beamforming pattern, but for the sake of clarity herein, the term beamforming pattern is utilised to described what is output from a subset of antenna elements that are being controlled using beamforming to produce a particular beamforming pattern.

[0049] As 15 degrees of beam steering has been applied the main lobe 305 points towards 75 degrees. For example, if combined with a mechanical downtilt of 15 degrees, the main lobe would point at the horizon.

[0050] As can be seen from the beamforming pattern 302, the 15 degrees beam steering results in a strong side lobes 303 and strong grating lobes 304i and 3042 in the resulting beamforming pattern 302. These strong unwanted lobes may result in the possibility for problems of line-of-sight blockers in the directions of these unwanted lobes.

[0051] Figure 4 illustrates how amplitude tapering may be applied amongst the four RF lines within the subset of antenna elements 204, at a cost of very low loss in main lobe gain, to lower the gain within the sidelobes. Another beamforming pattern 401 is illustrated in Figure 4 in comparison to the beamforming pattern 302. To produce the beamforming pattern 401 , amplitude tapering is applied to the beamforming pattern 302.

[0052] It can be seen from Figure 4 that when amplitude tapering is applied to the beamforming pattern 302, the amplitude of the sidelobes 303 can be reduced without causing much reduction in the amplitude of the main lobe 305. How much the amplitude of the sidelobes can be reduced depends on the chosen tapering window. It will be appreciated that if a line-of-sight blocker is located in the direction of one of the sidelobes, then utilising the beamforming pattern 401 will reduce the effects of the interference of that line-of-sight blocker as the gain in that direction in the beamforming pattern 401 is lower than the gain in that direction in the beamforming pattern 302.

[0053] It will be noted that the amplitude tapering is applied to lower the sidelobes but does not lower the gain of the grating lobes.

[0054] In the example illustrated in Figure 4 the four RF lines within the subset of antenna elements are exited with -4.8dB, OdB, OdB and -4.8dB respectively. This reduces the sidelobes by ~8dB with a directivity loss of only 0.2dB. The tapering loss is 1 ,7dB in this case, but since the tapering is applied after the Low-Noise Amplifier (LNA), the sensitivity loss is only ~0.2dB. Therefore, altogether only ~0.4dB in sensitivity is lost due to the tapering.

[0055] Figure 5 illustrates a beamforming pattern 501 with 10 degrees of beam steering and a beamforming pattern 502 with 20 degrees of beam steering. The beamforming pattern 302 from Figure 3 with 15 degrees beam steering is also shown. The beamforming patterns 501 , 502 and 302 are generated by applying beam steering to the first beamforming pattern 301 of Figure 3 (which does not have any beam steering). Shifting the direction of the main lobe 305 results in larger shifts in the grating lobes 304.1 and 304.2

[0056] One scenario is that a user resides in the main lobe 305 and a line-of-site blocker arrives in grating lobe 304.2. Depending on altitude angle of both the user and the line-of-site blocker, beampattern 501 , 502 or 302 will give the best signal quality and should be chosen for user communication. Figure 6 illustrates a method for controlling an antenna array at a network node. The antenna array may comprise the antenna array 200 as illustrated in Figure 2. However, it will be appreciated that the antenna array may be alternatively configured, and that the division of the antenna elements into sub-arrays and subsets may be performed differently to how it is illustrated in Figure 2.

[0057] The method may be performed by the network node, for example by a radio access network, RAN, node (e.g. base station, or an O-RAN network node) comprising the antenna array. In other examples, the method may be performed by another controller network node which is in communication with the network node comprising the antenna array.

[0058] The method of Figure 6 will be described with reference to the example implementations of antenna arrays illustrated in Figures 7 and 8. Figures 7 and 8 illustrate example antenna arrays 700 and 800 comprising a plurality of antenna elements, according to some embodiments. It will, however, be appreciated that Figures 7 and 8 are example implementations, and that other implementations are possible.

[0059] In Figure 7, four sub-arrays of two antenna elements together form a subset of antenna elements (similarly to as illustrated in Figure 2). However, the beamforming patterns illustrated in Figure 4 (which can be produced by the implementation illustrated in Figure 7) are based on windowing or symmetric amplitude tapering where the gain on each branch is taken from a (symmetric) window function. An alternative to this would be to optimize the taper to suppress only one sidelobe (on one side of the main lobe). This would, in general, require complex (so phase and amplitude) tapers (see for example, EP3266118B1 , WO2023 / 126668, WO2023 / 139397), and typically such complex tapers may require more degrees of freedom than what is provided in Figure 7. Therefore, Figure 8 provides an alternative implementation for an antenna array 800 in which a subset of antenna elements comprises six antenna elements, each with an individual port (e.g. no antenna subarrays are produced as in Figure 7). The structure of Figure 8 may be used to provide different beamforming patterns as will be described later with reference to Figures 9a and 9b.

[0060] Returning to Figure 6, in step 601 the method comprises controlling a first subset of antenna elements in the antenna array to provide a first beamforming pattern, wherein the first beamforming pattern is directed towards one or more first wireless devices in communication with the network node. In other words, the first beamforming pattern comprises a central lobe directed towards one or more first wireless devices. The subset of antenna elements may be utilized to perform hybrid, analog or digital BF.

[0061] It will also be appreciated that step 601 may comprise controlling a set of first subsets of antenna elements to provide the first beamforming pattern.

[0062] For example, in the example of Figure 7, the set of first subsets of antenna elements comprises all of the subsets that are outlined with dotted lines. These first subsets of antenna elements may therefore be controlled to each individually provide the first beamforming pattern. The first beamforming pattern may for example be the beamforming pattern 302 illustrated in Figure 3.

[0063] In the example of Figure 8, the set of first subsets of antenna elements comprises all of the subsets that are outlined with dotted lines. These first subsets of antenna elements may therefore be controlled to each individually provide the first beamforming pattern. The first beamforming pattern may for example be the beamforming pattern 901 illustrated in Figure 9a and 9b.

[0064] In the example of Figure 8 therefore, the first beamforming pattern 901 comprises a boresight beamforming pattern. However, it will be appreciated that in some examples, some elevation angle may be applied in the first beamforming pattern (e.g. beamforming pattern 302 as utilized in Figure 7).

[0065] For clarity, herein the control of a single first subset (e.g. subset 701 or subset 801) may be described. However, it will be appreciated that any control that is applied to a first subset 701 or 801 described herein may be equally applied to all of the first subsets in the set of first subsets.

[0066] It will be appreciated that the set of first subsets area are effectively being used to provide what may be considered normal operation of the antenna array. In other words, it is this set of first subsets that is being used to provide a suitable or preferable beamforming pattern for communication with one or more wireless devices.

[0067] In step 602 the method comprises controlling a second subset of antenna elements in the antenna array to provide a second beamforming pattern. The first beamforming pattern provides a first gain at a first angle associated with a first sidelobe or grating lobe of the first beamforming pattern (e.g. For the example beamforming pattern 302 from Figure 3, sidelobes 303 or grating lobes 304i or 3042), and the second beamforming pattern provides a second gain different from the first gain at the first angle.

[0068] In some examples, step 602 may comprise controlling a plurality of sets of one or more subsets of antenna elements in the antenna array such that each set is associated with a different beamforming pattern.

[0069] For example, in Figure 7 a first set of subsets comprises only one subset 702. This subset 702 may be configured to provide the beamforming pattern 401 which has a second gain that is lower than the first gain in the sidelobes 303 of the first beamforming pattern.

[0070] A second set of subsets comprises only one subset 703. The subset 703 may be configured to provide the beamforming pattern 502 in Figure 5 which has lower gains in the directions of for the grating lobes 304i and / or 3042.

[0071] A third set of subsets comprises only one subset 704. The subset 704 may be configured to provide the beamforming pattern 501 in Figure 5 which has a lower gain in the direction of the grating lobe 3042.

[0072] In the example of Figure 8 a first set of subsets comprises a subset 802 for which a small (e.g. 5 - 10 degrees) positive offset elevation angle (e.g. beam steering) is applied to the beamforming pattern 901. A second set of subsets comprises only one subset 803 for which a small (e.g. 5 - 10 degrees) negative offset elevation angle (e.g. beam steering) is applied to the beamforming pattern 901.

[0073] It will be appreciated that in some examples, step 602 comprises controlling a set of second subsets of antenna elements to provide a second beamforming pattern. In other words, each set of subsets may comprise more than one subset of antenna elements.

[0074] In the example of Figure 8 therefore a third set of subsets comprises subsets 804a and 804b. The subsets 804a and 804b may both be configured to provide the beamforming pattern 902 of Figure 9. In the beamforming pattern 902 it can be seen that the gain a first sidelobe 904a is suppressed compared to the beamforming pattern 901. A fourth set of subsets comprises the subsets 805a and 805b. The subsets 805a and 805b may be configured to provide the beamforming pattern 903 of Figure 9. In the beamforming pattern 903 it can be seen that the gain in a second sidelobe 904b is suppressed compared to the beamforming pattern 901. Furthermore, the first sidelobe 904a is not suppressed in the beamforming pattern 903. In such a case it is therefore possible to detect whether a line-of-sight blocker has entered the first sidelobe 904a or the second sidelobe 904b, regardless of the fact that these sidelobes are adjacent sidelobes.

[0075] The tapers for the beamforming patterns 902 and 903 may be found according to methods described in WO2023 / 126668 . This specificity in the direction of the tapering may be achievable due to the increased degrees of freedom provided by having the 6 ports available to adjust the signals being output by each of the antenna elements in the subset. It will be appreciated that the tapering coefficients only depend on the allocated beam and its sidelobe positions, which is something that is well defined by the array geometry and can therefore be calculated in advanced and stored in a table.

[0076] In step 603, responsive to a second power level detected on the second subset of antenna elements being less than a first power level detected on the first subset of antenna elements, the method comprises controlling the first subset of antenna elements to provide a third beamforming pattern. In other words, detecting a lower power level on the second subset of antenna elements than the first subset may be indicative of a line- of-sight blocker located in the direction at which the second beamforming pattern has a lower gain - e.g. at the first angle.

[0077] It will be appreciated that where there are a plurality of sets of one or more subsets of antenna elements in the antenna array, and each set is associated with a different beamforming pattern, step 603 may comprise determining whether the first power level detected on the first subset of antenna elements is different to a power level detected on any other set and controlling the first subset of antenna elements to provide a fourth beamforming pattern based on which set of subsets had the lowest power level. In other words, the beamforming pattern being provided by the subset of antenna elements associated with the lower detected power level may be utilized to determine the third beamforming pattern for the first subset (or the set of first subsets) of antenna elements. It will be appreciated that, in order to mitigate the interference effects of the potential line- of-sight block, in step 603, the method may switch the first subset of antenna elements so that they provide the third beamforming pattern. The third beamforming pattern may be designed such that is has a lower gain at the first angle. In other words, the third beamforming pattern may be configured to provide a third gain at the first angle, wherein the third gain is lower than the first gain. In some examples, the third beamforming pattern may be the second beamforming pattern.

[0078] Figure 10 illustrates an example implementation of the method of Figure 6. In this example it is assumed that the steps 601 and 602 have already been performed. For example, the method of Figure 10 may be performed utilizing the antenna arrays set up in either of Figures 7 or 8.

[0079] In step 1001 , the method comprises determining whether a first power level detected on a first subset of antenna elements meeting a first threshold condition. For example, the first threshold condition may be that the first power level is greater than a first threshold power level. It will be appreciated that interference from a blocker is occurring at a high enough level, the ADC connected to the first subset of antenna elements may start saturating. Step 1001 may therefore monitor the first power level measured at the ADC connected to the first subset of antenna elements. If the first threshold condition is not met it may be assumed that there is no line-of sight-blocker or that the interference caused by such a blocker is not high enough to be of concern, and the method may continue to perform step 1001 to monitor the first power level.

[0080] In the examples of Figures 7 or 8 it will be appreciated that any one or more of the set of first subsets (e.g. those outlined with a dotted line) may be the first subset referred to in step 1001.

[0081] If in step 1001 it is determined that the first threshold condition is met (e.g the first power level is greater than the first threshold power level) the method may pass to step 1002.

[0082] In step 1002, the instantaneous power level on each subset of antenna elements within the array may be recorded.

[0083] In step 1003, the method may comprise determining detecting whether the first power level is recorded on all of the set of first subsets. For example, in the example of Figure 7, step 1003 may comprise checking that the same power level is being recorded at all of the subsets outlined with dotted lines. It will be appreciated that the power levels may be considered the same if they fall within a predetermined margin. The size of the margin may be a design choice and may be large enough to account for any error involved in the detection of the power levels.

[0084] If the first power level is not recorded on all of the set of first subsets this would not be indicative of a line-of sight blocker being the cause of the power level surging. Instead, the surging power level may be caused by a plurality of wireless devices collectively contributing to the increased power level. In this case therefore the method may pass to step 1004 in which the gain on affected subsets, which may be those first subsets for which the first power level has met the first threshold criterion are reduced. In some examples, after performing the step 1004, the method of Figure 11 may be performed in order to monitor when normal gain can be resumed at those first subsets for which the gain has been reduced.

[0085] After step 1004 the method may also return to step 1001. This enables the method to reduce the gain even further if it is determined that the gain reduction performed in step 1004 was not sufficient. Returning to step 1001 also enables for the detection of any line- of-sight blockers than may appear.

[0086] If, however, the first power level on all of the set of first subsets is the same at step 1003, the method may pass to step 1005.

[0087] In step 1005, the method comprises determining whether the power level detected on any of the other subsets of antenna elements (e.g. those providing different beamforming patterns to the first subset of antenna elements) is lower than the first power level.

[0088] For example, step 1005 may comprise determining whether the second power level detected on a second subset of antenna elements (providing a different beamforming pattern to the first subset of antenna elements) is less than the first power level. It will be appreciated that, if the power level recorded on more than one subset of antenna elements (each providing different beamforming patterns) is lower than the first power level, step 1005 may comprise determining the lowest power level as the second power level. It will be appreciated that step 1005 may comprise determining that the second power level is lower than the first power level if the second power level is less than the first power level by a predetermined margin. This margin may prevent ping-ponging between applying different beamforming patterns unnecessarily.

[0089] If it is determined in step 1005 that the power level detected on all of the other subsets of antenna elements (e.g. those providing different beamforming patterns to the first subset of antenna elements) is not lower than the first power level (or not lower by at least a predetermined margin), it may be assumed that the line-of-sight blocker is located in the main lobe of the first beamforming pattern.

[0090] In this case the method may pass to step 1004 in which the gain of the affected subsets (which in this example may be all subsets) may be reduced in order to avoid saturating the ADCs. However, as the line-of-sight blocker is located in the main beam, adjusting the beamforming pattern may not help to reduce the interference. As previously mentioned, after step 1004 the method may also return to step 1001. This enables the method to reduce the gain even further if it is determined that the gain reduction performed in step 1004 was not sufficient. Returning to step 1001 also enables for the detection of any other line-of-sight blockers than may appear.

[0091] However, if it is determined in step 1005 that a second power level is lower than the first power level, the method may pass to step 1006.

[0092] In step 1006, the method may comprise determining a third beamforming pattern. As described with reference to Figure 6, the third beamforming pattern may comprise beamforming pattern in which the gain at a first angle associated with the line-of-sight blocker is less than the gain provided by the first beamforming pattern at that angle. For example, looking at the example of Figure 8, if the power level detected on the set of subsets 804a and 804b (providing beamforming pattern 902) is less that the power level detected on the subset 801 (providing beamforming pattern 901), it may be determined that the line of sight blocked is located within the sidelobe 904a.

[0093] The third beamforming pattern may therefore be a beamforming pattern for which the gain in the direction of the sidelobe 904a is reduced. It will be appreciated that the third beamforming pattern may comprise he second beamforming pattern (which in this example would be the beamforming pattern 902), however in some examples other beamforming patterns may be designed. For example, if concurrently with the power level detected on subsets 804a and 804b being less than the power level detected on subset 801 , the power level detected on subsets 805a and 805b is also reduced compared to subset 801 , this may suggest that there are two line of sight blockers present, one in the direction of sidelobe 904a and one in the direction of sidelobe 904b. In this case, the third beamforming pattern may be designed to reduce the gain the direction of both sidelobes 904a and 904b.

[0094] If a third beamforming pattern cannot be determined, the method passes to step 1004 in which the gain of the affected subset (which in this case may be the set of first subsets) may be reduced. For example, tapering and normal gain reduction is normally applied with the same hardware resources, e.g. at an attenuator in an RF chain. Therefore, if the gain has already been lowered on all receiver paths (example due to an in-beam blocker or high signal), then it may not be possible to apply tapering.

[0095] However, if a third beamforming pattern is determined in step 1006 the method passes to step 1007 which comprises controlling the first subset of antenna elements (or the set of first subsets) to provide the third beamforming pattern. Step 1007 comprises an example implementation of step 603 of Figure 6.

[0096] In some examples, step 1007 further comprises responsive to the second power level being lower than the first power level, controlling the second subset of antenna elements to provide the first beamforming pattern. In other words, whilst the first subset of antenna elements are switched to provide the third beamforming pattern to avoid the interference caused by the line-of-sight blocker, the second subset of antenna elements may be switched to provide the first beamforming pattern so that the interference being caused by the line-of-sight blocker can be monitored. The monitoring of the line-of-sight blocker will be described in more detail with reference to Figure 11.

[0097] It will also be appreciated that after performing 1007 the method may return to step 1001. This may enable the detection of any further line-of-sight blockers or enable the adjustment of the gain in addition to the use of the third beamforming pattern.

[0098] Figure 11 illustrates an example method for monitoring the interference caused by a line-of-sight blocker. The method of Figure 11 may be performed after performing step 1004 or step 1007 in the Figure 10. In step 1101 , the method comprises measuring the power level on a subset of antenna elements that is providing the first beamforming pattern. In some examples, (e.g. where step 1007 was the previous performed operation) step 1101 comprises measuring a third power level on the second subset of the antenna elements. It will be appreciated that the second subset of antenna elements may now be providing the first beamforming pattern. The second subset may therefore be able to monitor the interference that is being caused by the line-of-sight blocker on the first beamforming pattern.

[0099] However, in some examples, (e.g. where step 1004) was the previous performed operation, step 1101 comprises measuring the power level provided on the first subset of antenna elements. For example, the gain on the first subset of antenna elements may have been lowered as described with reference to Figure 10.

[0100] In step 1102 the method comprises determining whether the measured power level meets a second threshold condition. The second threshold condition may be the power level dropping below a second predetermined threshold. The second predetermined threshold may be the same as the first predetermined threshold utilized in step 1001 of Figure 10. However, in some examples, the second predetermined threshold may be lower than the first predetermined threshold.

[0101] Responsive to the power level not meeting the second threshold condition the method passes to step 1103 in which a wait time is implemented before returning to step 1101.

[0102] Responsive to the power level meeting the second threshold condition, the method may pass to step 1104 which may comprise (if step 1007 was implemented prior to the method of Figure 11)) controlling the first subset of antenna elements to provide the first beamforming pattern and / or the second subset of antenna elements to provide the second beamforming pattern. In other words, if the third power level drops below the second predetermined threshold, this may be considered indicative of the line-of-sight block moving out of an interfering position, and so normal operation of the antenna array can be assumed.

[0103] Alternatively, step 1104 may comprise increasing the gain of applied to the first subset of antenna elements (if step 1004 was implemented prior to the method of Figure 11). In other words, if the gain applied to the first subset of antenna elements was reduced, but the gain measured at the first subset of antenna elements has once again dropped below a threshold level, the gain may be reinstated to assume normal operation.

[0104] Figure 12 illustrates a method for resetting the beamforming provided by an antenna array. The method of Figure 12 may be performed in conjunction with the methods of Figures 6, 10 and 11.

[0105] In step 1201 the method comprises determining whether an updated elevation angle is required for the first subset of antenna elements. In other words, determining whether the one or more wireless devices that the first beamforming pattern is designed for communication with have moved and that therefore beam steering is required to ensure efficient communication with the one or more wireless devices.

[0106] If no updated elevation angle is required, the method returns to step 1201.

[0107] Responsive to updating the elevation angle associated with the first subset of antenna elements the method passes to step 1202 in which normal operation of the antenna array is resumed. For example, step 1202 may comprise controlling the first subset of antenna elements to provide the first beamforming pattern. Step 1202 may also comprise reversing any gain adjustments made in step 1004 of Figure 10.

[0108] Figure 13 shows a controller node 1300 in accordance with some embodiments. The controller node may comprise or be comprised within a network node. As used herein, a network node refers to equipment capable, configured, arranged and / or operable to communicate directly or indirectly with a UE and / or with other network nodes or equipment, in a telecommunication network. Examples of network nodes include, but are not limited to, access points (APs) (e.g., radio access points), base stations (BSs) (e.g., radio base stations, Node Bs, evolved Node Bs (eNBs) and NR NodeBs (gNBs)), O-RAN nodes or components of an O-RAN node (e.g., 0-Rll, 0-Dll, O-CU).

[0109] Base stations may be categorized based on the amount of coverage they provide (or, stated differently, their transmit power level) and so, depending on the provided amount of coverage, may be referred to as femto base stations, pico base stations, micro base stations, or macro base stations. A base station may be a relay node or a relay donor node controlling a relay. A network node may also include one or more (or all) parts of a distributed radio base station such as centralized digital units, distributed units (e.g., in an O-RAN access node) and / or remote radio units (RRUs), sometimes referred to as Remote Radio Heads (RRHs). Such remote radio units may or may not be integrated with an antenna as an antenna integrated radio. Parts of a distributed radio base station may also be referred to as nodes in a distributed antenna system (DAS).

[0110] Other examples of network nodes include multiple transmission point (multi-TRP) 5G access nodes, multi-standard radio (MSR) equipment such as MSR BSs, network controllers such as radio network controllers (RNCs) or base station controllers (BSCs), base transceiver stations (BTSs), transmission points, transmission nodes, multi- cell / multicast coordination entities (MCEs), Operation and Maintenance (O&M) nodes, Operations Support System (OSS) nodes, Self-Organizing Network (SON) nodes, positioning nodes (e.g., Evolved Serving Mobile Location Centers (E-SMLCs)), and / or Minimization of Drive Tests (MDTs).

[0111] The controller node 1300 includes a processing circuitry 1302, a memory 1304, a communication interface 1306, and a power source 1308. The controller node 1300 may be composed of multiple physically separate components (e.g., a NodeB component and a RNC component, or a BTS component and a BSC component, etc.), which may each have their own respective components. In certain scenarios in which the controller node 1300 comprises multiple separate components (e.g., BTS and BSC components), one or more of the separate components may be shared among several network nodes. For example, a single RNC may control multiple NodeBs. In such a scenario, each unique NodeB and RNC pair, may in some instances be considered a single separate network node. In some embodiments, the controller node 1300 may be configured to support multiple radio access technologies (RATs). In such embodiments, some components may be duplicated (e.g., separate memory 1304 for different RATs) and some components may be reused (e.g., a same antenna 1310 may be shared by different RATs). The controller node 1300 may also include multiple sets of the various illustrated components for different wireless technologies integrated into controller node 1300, for example GSM, WCDMA, LTE, NR, WiFi, Zigbee, Z-wave, LoRaWAN, Radio Frequency Identification (RFID) or Bluetooth wireless technologies. These wireless technologies may be integrated into the same or different chip or set of chips and other components within controller node 1300.

[0112] The processing circuitry 1302 may comprise a combination of one or more of a microprocessor, controller, microcontroller, central processing unit, digital signal processor, application-specific integrated circuit, field programmable gate array, or any other suitable computing device, resource, or combination of hardware, software and / or encoded logic operable to provide, either alone or in conjunction with other controller node 1300 components, such as the memory 1304, to provide controller node 1300 functionality. For example, the processing circuitry 1302 may be configured to cause the controller node to perform the methods as described with reference to any one or more of Figures 6, 11 , 12 or 13.

[0113] In some embodiments, the processing circuitry 1302 includes a system on a chip (SOC). In some embodiments, the processing circuitry 1302 includes one or more of radio frequency (RF) transceiver circuitry 1312 and baseband processing circuitry 1314. In some embodiments, the radio frequency (RF) transceiver circuitry 1312 and the baseband processing circuitry 1314 may be on separate chips (or sets of chips), boards, or units, such as radio units and digital units. In alternative embodiments, part or all of RF transceiver circuitry 1312 and baseband processing circuitry 1314 may be on the same chip or set of chips, boards, or units.

[0114] The memory 1304 may comprise any form of volatile or non-volatile computer-readable memory including, without limitation, persistent storage, solid-state memory, remotely mounted memory, magnetic media, optical media, random access memory (RAM), readonly memory (ROM), mass storage media (for example, a hard disk), removable storage media (for example, a flash drive, a Compact Disk (CD) or a Digital Video Disk (DVD)), and / or any other volatile or non-volatile, non-transitory device-readable and / or computerexecutable memory devices that store information, data, and / or instructions that may be used by the processing circuitry 1302. The memory 1304 may store any suitable instructions, data, or information, including a computer program, software, an application including one or more of logic, rules, code, tables, and / or other instructions capable of being executed by the processing circuitry 1302 and utilized by the controller node 1300. The memory 1304 may be used to store any calculations made by the processing circuitry 1302 and / or any data received via the communication interface 1306. In some embodiments, the processing circuitry 1302 and memory 1304 is integrated.

[0115] The communication interface 1306 is used in wired or wireless communication of signaling and / or data between a network node, access network, and / or UE. As illustrated, the communication interface 1306 comprises port(s) / terminal(s) 1316 to send and receive data, for example to and from a network over a wired connection. The communication interface 1306 also includes radio front-end circuitry 1318 that may be coupled to, or in certain embodiments a part of, the antenna 1310. Radio front-end circuitry 1318 comprises filters 1320 and amplifiers 1322. The radio front-end circuitry 1318 may be connected to an antenna 1310 and processing circuitry 1302. The radio front-end circuitry may be configured to condition signals communicated between antenna 1310 and processing circuitry 1302. The radio front-end circuitry 1318 may receive digital data that is to be sent out to other network nodes or UEs via a wireless connection. The radio front-end circuitry 1318 may convert the digital data into a radio signal having the appropriate channel and bandwidth parameters using a combination of filters 1320 and / or amplifiers 1322. The radio signal may then be transmitted via the antenna 1310. Similarly, when receiving data, the antenna 1310 may collect radio signals which are then converted into digital data by the radio front-end circuitry 1318. The digital data may be passed to the processing circuitry 1302. In other embodiments, the communication interface may comprise different components and / or different combinations of components.

[0116] In certain alternative embodiments, the controller node 1300 does not include separate radio front-end circuitry 1318, instead, the processing circuitry 1302 includes radio frontend circuitry and is connected to the antenna 1310. Similarly, in some embodiments, all or some of the RF transceiver circuitry 1312 is part of the communication interface 1306. In still other embodiments, the communication interface 1306 includes one or more ports or terminals 1316, the radio front-end circuitry 1318, and the RF transceiver circuitry 1312, as part of a radio unit (not shown), and the communication interface 1306 communicates with the baseband processing circuitry 1314, which is part of a digital unit (not shown).

[0117] The antenna 1310 may include one or more antennas, or antenna arrays, configured to send and / or receive wireless signals. The antenna 1310 may be coupled to the radio front-end circuitry 1318 and may be any type of antenna capable of transmitting and receiving data and / or signals wirelessly. In certain embodiments, the antenna 1310 is separate from the controller node 1300 and connectable to the controller node 1300 through an interface or port.

[0118] The antenna 1310, communication interface 1306, and / or the processing circuitry 1302 may be configured to perform any receiving operations and / or certain obtaining operations described herein as being performed by the network node. Any information, data and / or signals may be received from a UE, another network node and / or any other network equipment. Similarly, the antenna 1310, the communication interface 1306, and / or the processing circuitry 1302 may be configured to perform any transmitting operations described herein as being performed by the network node. Any information, data and / or signals may be transmitted to a UE, another network node and / or any other network equipment.

[0119] The power source 1308 provides power to the various components of controller node 1300 in a form suitable for the respective components (e.g., at a voltage and current level needed for each respective component). The power source 1308 may further comprise, or be coupled to, power management circuitry to supply the components of the controller node 1300 with power for performing the functionality described herein. For example, the controller node 1300 may be connectable to an external power source (e.g., the power grid, an electricity outlet) via an input circuitry or interface such as an electrical cable, whereby the external power source supplies power to power circuitry of the power source 1308. As a further example, the power source 1308 may comprise a source of power in the form of a battery or battery pack which is connected to, or integrated in, power circuitry. The battery may provide backup power should the external power source fail.

[0120] Embodiments of the controller node 1300 may include additional components beyond those shown in Figure 13 for providing certain aspects of the network node’s functionality, including any of the functionality described herein and / or any functionality necessary to support the subject matter described herein. For example, the controller node 1300 may include user interface equipment to allow input of information into the controller node 1300 and to allow output of information from the controller node 1300. This may allow a user to perform diagnostic, maintenance, repair, and other administrative functions for the controller node 1300. In some embodiments providing a core network node, such as core network node 108 of FIG. QQ1 , some components, such as the radio front-end circuitry 1318 and the RF transceiver circuitry 1312 may be omitted.

[0121] Figure 14 is a block diagram illustrating a controller node 1400 according to some embodiments. The controller node 1400 can control an antenna array at a network node. The controller node 1400 comprises a first controlling module 1402 configured to controlling a first subset of antenna elements in the antenna array to provide a first beamforming pattern, wherein the first beamforming pattern is directed towards one or more first wireless devices in communication with the network node.

[0122] The controller node 1400 further comprises a second controlling module 1404 configured to control a second subset of antenna elements in the antenna array to provide a second beamforming pattern, wherein the first beamforming pattern provides a first gain at a first angle associated with a first sidelobe of the first beamforming pattern, and the second beamforming pattern provides a second gain lower than the first gain at the first angle.

[0123] The controller node 1400 comprises a third controlling module 1406 configured to responsive to a second power level detected on the second subset of antenna elements being less than a first power level detected on the first subset of antenna elements, control the first subset of antenna elements to provide a third beamforming pattern.

[0124] The controller node 1400 may operate in the manner described herein in respect of an controller node.

[0125] There is also provided a computer program comprising instructions which, when executed on a least one processor (such as the processing circuitry 1301 of the controller node 1300 described earlier), cause the processor to carry out at least part of the method(s) described herein. According to some embodiments there is provided a carrier containing the computer program. In some embodiments, the carrier can be any one of an electronic signal, an optical signal, an electromagnetic signal, an electrical signal, a radio signal, a microwave signal, or a computer-readable medium. There is also provided a (for example, tangible and / or non-transient) computer-readable medium comprising instructions which, when executed by at least one processor, cause the at least one processor to perform at least part of the method(s) described herein.

[0126] It should be noted that the above-mentioned embodiments illustrate rather than limit the invention, and that those skilled in the art will be able to design many alternative embodiments without departing from the scope of the appended claims. The word “comprising” does not exclude the presence of elements or steps other than those listed in a claim, “a” or “an” does not exclude a plurality, and a single processor or other unit may fulfil the functions of several units recited in the claims. Any reference signs in the claims shall not be construed so as to limit their scope.

Claims

CLAIMS1. A method performed by a controller node for controlling an antenna array at a network node, the method comprising: controlling (601) a first subset of antenna elements in the antenna array to provide a first beamforming pattern, wherein the first beamforming pattern is directed towards one or more first wireless devices in communication with the network node; controlling (602) a second subset of antenna elements in the antenna array to provide a second beamforming pattern, wherein the first beamforming pattern provides a first gain at a first angle associated with a first sidelobe of the first beamforming pattern, and the second beamforming pattern provides a second gain lower than the first gain at the first angle; and responsive to a second power level detected on the second subset of antenna elements being less than a first power level detected on the first subset of antenna elements, controlling (603) the first subset of antenna elements to provide a third beamforming pattern.

2. The method as claimed in claim 1 further comprising: determining whether the second power level is less than the first power level.

3. The method as claimed in claim 1 or 2, wherein the third beamforming pattern is configured to provide a third gain at the first angle, wherein the third gain is lower than the first gain.

4. The method as claimed in claim 1 to 3 wherein the third beamforming pattern comprises the second beamforming pattern.

5. The method as claimed in any one of claims 1 to 4, further comprising: controlling a set of first subsets of antenna elements in the antenna array to provide the first beamforming pattern, and determining whether the first power level is different to the second power level responsive to detecting (1003) the first power level on all of the set of first subsets of antenna elements.

6. The method as claimed in any of claims 1 to 5, further comprising: determining whether the first power level is different to the second power level responsive to the first power level meeting (1001) a first threshold condition.

7. The method as claimed in any one of claims 1 to 6 further comprising: responsive to the second power level being lower than the first power level, controlling (1007) the second subset of antenna elements to provide the first beamforming pattern.

8. The method as claimed in claim 7 further comprising: responsive to controlling the second subset of antenna elements to provide the first beamforming pattern, monitoring a third power level on the second subset of the antenna elements, and responsive to the third power level meeting a second threshold condition (1102), controlling (1104) the first subset of antenna elements to provide the first beamforming pattern.

9. The method as claimed in claim 8 further comprising responsive to the third power level meeting the second threshold condition, controlling the second subset of antenna elements to provide the second beamforming pattern.

10. The method as claimed in any one of claims 1 to 9 further comprising: after controlling the first subset of antenna elements to provide the third beamforming pattern, and responsive to changing (1201) an elevation angle associated with the first subset of antenna elements, controlling (1202) the first subset of antenna elements to provide the first beamforming pattern.

11. The method as claimed in any preceding claim further comprising: controlling a plurality of sets of one or more subsets of antenna elements in the antenna array such that each set is associated with a different beamforming pattern.

12. The method as claimed in one of 11 when dependent on claim 2, further comprising:determining whether the first power level detected on the first subset of antenna elements is different to a power level detected on any other set.

13. The method as claimed in claim 12 further comprising: controlling the first subset of antenna elements to provide a fourth beamforming pattern associated with a set on which a lowest power level was detected.

14. A controller node (1300) for controlling an antenna array at a network node, the controller node comprising processing circuitry (1302) and a memory (1304), the memory containing instructions executable by the processing circuitry whereby the controller node is operable to: control (601) a first subset of antenna elements in the antenna array to provide a first beamforming pattern, wherein the first beamforming pattern is directed towards one or more first wireless devices in communication with the network node; control (602) a second subset of antenna elements in the antenna array to provide a second beamforming pattern, wherein the first beamforming pattern provides a first gain at a first angle associated with a first sidelobe of the first beamforming pattern, and the second beamforming pattern provides a second gain lower than the first gain at the first angle; and responsive to a second power level detected on the second subset of antenna elements being less than a first power level detected on the first subset of antenna elements, control (603) the first subset of antenna elements to provide a third beamforming pattern.

15. The controller node as claimed in claim 14 wherein the memory further contains instructions executable by the processing circuitry whereby the controller node is operable to perform the method as claimed in any one of claims 2 to 13.

16. A radio access network node comprising a controller node as claimed in claim 14 or 15.

17. A computer program, comprising instructions which, when executed on at least one processor, cause the at least one processor to carry out a method according to any of claims 1 to 13.

18. A carrier containing the computer program according to claim 17, wherein the carrier comprises one of an electronic signal, optical signal, radio signal or computer readable storage medium.

19. A computer-readable medium comprising instructions that, when executed on at least one processor, cause the at least one processor to perform the method according to any of claims 1 to 13.

20. A computer program product comprising non transitory computer readable media having stored thereon a computer program according to claim 17.

Images